#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstdlib>
#include<algorithm>
#include<cstring>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<queue>
using namespace std;
int a,b;
pair<int,int> p1,p2;
pair<int,int> calc(int x)
{pair<int,int> ans;int y=sqrt(x*1.0);if ((y&1)&&(y*y==x)){ans.first=ans.second=(-(y-1)>>1);return ans;}if ((y&1)==0) y--;int p=y*y;ans.first=ans.second=(-(y-1)>>1);if (x-p<=(y+1)){ans.second--;ans.first+=(x-p)-1;return ans;}p+=(y+1);ans.first+=y;ans.second--;if (x-p<=y+1){ans.second+=(x-p);return ans;}ans.second+=(y+1);p+=(y+1);if (x-p<=y+1){ans.first-=(x-p);return ans;}ans.first-=(y+1);p+=y+1;ans.second-=(x-p);return ans;
}
int main()
{scanf("%d%d",&a,&b);p1=calc(a);p2=calc(b);printf("%d\n",abs(p1.first-p2.first)+abs(p1.second-p2.second));return 0;
}

#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstdlib>
#include<algorithm>
#include<cstring>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<queue>
using namespace std;
#define y1 khjk
#define y2 kjkj
struct point
{double x,y;point(){}point(double _x,double _y):x(_x),y(_y){}point operator -(const point &b) const{return point(x-b.x,y-b.y);}double operator *(const point &b) const{return x*b.x+y*b.y;}double operator ^(const point &b) const{return x*b.y-y*b.x;}
};
struct line
{point s,e;double a,b,c;line(){}line (point _s,point _e):s(_s),e(_e){a=e.y-s.y;b=s.x-e.x;c=e.x*s.y-s.x*e.y;}
};
double xmult(point p0,point p1,point p2)
{return (p1-p0)^(p2-p0);
}
const double eps = 1e-1;
double sgn(double x)
{if(fabs(x) < eps)return 0;if(x < 0)return -1;else return 1;
}
bool inter(line l1,line l2)
{returnmax(l1.s.x,l1.e.x) >= min(l2.s.x,l2.e.x) &&max(l2.s.x,l2.e.x) >= min(l1.s.x,l1.e.x) &&max(l1.s.y,l1.e.y) >= min(l2.s.y,l2.e.y) &&max(l2.s.y,l2.e.y) >= min(l1.s.y,l1.e.y) &&sgn((l2.s-l1.s)^(l1.e-l1.s))*sgn((l2.e-l1.s)^(l1.e-l1.s)) <= 0 &&sgn((l1.s-l2.s)^(l2.e-l2.s))*sgn((l1.e-l2.s)^(l2.e-l2.s)) <= 0;
}
bool samepoint(point p1,point p2)
{if (fabs(p1.x-p2.x)>eps) return false;if (fabs(p1.y-p2.y)>eps) return false;return true;
}
double cross(point sp,point ep,point op)
{return (sp.x-op.x)*(ep.y-op.y)-(sp.y-op.y)*(ep.x-op.x);
}
double area(point p1,point p2,point p3)
{return fabs(cross(p1,p2,p3))/2;
}
point intersection(line u,line v)
{point p;p.x=(cross(v.e,u.e,u.s)*v.s.x-cross(v.s,u.e,u.s)*v.e.x)/(cross(v.e,u.e,u.s)-cross(v.s,u.e,u.s));p.y=(cross(v.e,u.e,u.s)*v.s.y-cross(v.s,u.e,u.s)*v.e.y)/(cross(v.e,u.e,u.s)-cross(v.s,u.e,u.s));return p;
}
point interpoint(line l1, line l2)
{point tmp;if(fabs(l1.b)<eps){tmp.x=-l1.c/l1.a;tmp.y=(-l2.c-l2.a*tmp.x)/l2.b;}else{tmp.x=(l1.c*l2.b-l1.b*l2.c)/(l1.b*l2.a-l2.b*l1.a);tmp.y=(-l1.c-l1.a*tmp.x)/l1.b;}return tmp;
}
double findx(double y,line l)
{return (-l.c-l.b*y)/l.a;
}
double findy(double x,line l)
{if (fabs(l.b)<eps)return -1e250;return (-l.c-l.a*x)/l.b;
}
point tcircle(point pt1, point pt2, point pt3, double &radius)
{double x1 = pt1.x, x2 = pt2.x, x3 = pt3.x;double y1 = pt1.y, y2 = pt2.y, y3 = pt3.y;double a = x1 - x2;double b = y1 - y2;double c = x1 - x3;double d = y1 - y3;double e = ((x1 * x1 - x2 * x2) + (y1 * y1 - y2 * y2)) / 2.0;double f = ((x1 * x1 - x3 * x3) + (y1 * y1 - y3 * y3)) / 2.0;double det = b * c - a * d;if( fabs(det) <eps){radius = -1;return point(0,0);}double x0 = -(d * e - b * f) / det;double y0 = -(a * f - c * e) / det;radius = hypot(x1 - x0, y1 - y0);return point(x0, y0);
}
int n,cnt1=0,cnt2=0;
point p1[1100],p2[1100];
double dis(point p1,point p2)
{return sqrt((p2.x-p1.x)*(p2.x-p1.x)+(p2.y-p1.y)*(p2.y-p1.y));
}
void calc(point P,point Q)
{double r=dis(P,Q)/2;point p;p.x=(P.x+Q.x)/2;p.y=(P.y+Q.y)/2;bool can=true;int l;for (l=1;l<=cnt1;l++)if ((p1[l].x-p.x)*(p1[l].x-p.x)+(p1[l].y-p.y)*(p1[l].y-p.y)-r*r>eps){can=false;break;}if (!can) return;for (l=1;l<=cnt2;l++)if (r*r-(p2[l].x-p.x)*(p2[l].x-p.x)-(p2[l].y-p.y)*(p2[l].y-p.y)>eps){can=false;break;}if (can){puts("No");exit(0);}}
bool onSegment(point Pi , point Pj , point Q)
{if((Q.x - Pi.x) * (Pj.y - Pi.y) == (Pj.x - Pi.x) * (Q.y - Pi.y)&& min(Pi.x , Pj.x) <= Q.x && Q.x <= max(Pi.x , Pj.x)&& min(Pi.y , Pj.y) <= Q.y && Q.y <= max(Pi.y , Pj.y))return true;elsereturn false;
}
int main()
{scanf("%d",&n);int i,j,k,l;for (i=1;i<=n;i++){point p;scanf("%lf%lf",&p.x,&p.y);char c[3];scanf("%s",c);if (c[0]=='I')p1[++cnt1]=p;else p2[++cnt2]=p;}if (cnt1<=1){puts("No");return 0;}else if (cnt1==2){calc(p1[1],p1[2]);bool can=true;for (i=1;i<=cnt2;i++)if (onSegment(p1[1],p1[2],p2[i])){can=false;break;}if (can)puts("No");else puts("Yes");return 0;}int cnt3=cnt1;cnt3++;p1[cnt3].x=10000;p1[cnt3].y=10000;cnt3++;p1[cnt3].x=-10000;p1[cnt3].y=10000;cnt3++;p1[cnt3].x=10000;p1[cnt3].y=-10000;cnt3++;p1[cnt3].x=-10000;p1[cnt3].y=-10000;cnt3++;p1[cnt3].x=0;p1[cnt3].y=-10000;cnt3++;p1[cnt3].x=0;p1[cnt3].y=10000;cnt3++;p1[cnt3].x=10000;p1[cnt3].y=0;cnt3++;p1[cnt3].x=-10000;p1[cnt3].y=-0;for (i=1;i<=cnt3-2;i++)for (j=i+1;j<=cnt3-1;j++)for (k=j+1;k<=cnt3;k++){double r;point p=tcircle(p1[i],p1[j],p1[k],r);if (r==-1){calc(p1[i],p1[j]);calc(p1[i],p1[k]);calc(p1[j],p1[k]);continue;}if (r!=-1){bool can=true;for (l=1;l<=cnt1;l++)if ((p1[l].x-p.x)*(p1[l].x-p.x)+(p1[l].y-p.y)*(p1[l].y-p.y)-r*r>eps){can=false;break;}if (!can) continue;for (l=1;l<=cnt2;l++)if (r*r-(p2[l].x-p.x)*(p2[l].x-p.x)-(p2[l].y-p.y)*(p2[l].y-p.y)>eps){can=false;break;}if (can){puts("No");return 0;}}}puts("Yes");return 0;
}

#include <bits/stdc++.h>using namespace std;#define rep(i, a, b) for (int i(a); i <= (b); ++i)
#define dec(i, a, b)    for (int i(a); i >= (b); --i)   typedef long long LL;const int N = 2e4 + 10;
const char* ch = " FUT";int an[6][6], oo[6][6], im[6][6], eq[6][6];
int mul[6][6];
int f[N][4][4];
int cnt;
int c[6][6];
int ct;
int T;set <int> mp;void init(){int s = 1;rep(i, 1, 3){rep(j, 1, 3){mul[i][j] = s;s *= 10;}}
}inline int get(int cnt){int ret = 0;rep(i, 1, 3) rep(j, 1, 3) ret += f[cnt][i][j] * mul[i][j];return ret;
}inline void work(int cnt){int h = get(cnt);mp.insert(h);
}inline void output(int cnt){dec(i, 3, 1) dec(j, 3, 1) printf("%d", f[cnt][i][j]); putchar(10);
}inline void out(){dec(i, 3, 1) dec(j, 3, 1) printf("%d", c[i][j]); putchar(10);
}inline void check(){int ret = 0;rep(i, 1, 3) rep(j, 1, 3) ret += c[i][j] * mul[i][j];if (mp.count(ret)) return;
//  out();mp.insert(ret);++cnt;rep(i, 1, 3) rep(j, 1, 3) f[cnt][i][j] = c[i][j];
}void judge(){int ret = 0;rep(i, 1, 3) rep(j, 1, 3) ret += c[i][j] * mul[i][j];if (mp.count(ret)) puts("definable");else puts("undefinable");}int main(){freopen("1.txt", "r", stdin);freopen("2.txt", "w", stdout);init();rep(i, 1, 3) rep(j, 1, 3){an[i][j] = min(i, j);oo[i][j] = max(i, j);eq[i][j] = (i == j) ? 3 : 1;}im[1][1] = im[1][2] = im[1][3] = 3;im[2][1] = 2; im[2][2] = im[2][3] = 3;im[3][1] = 1; im[3][2] = 2; im[3][3] = 3;++cnt; rep(i, 1, 3) rep(j, 1, 3) f[cnt][i][j] = im[i][j];  work(cnt);++cnt; rep(i, 1, 3) rep(j, 1, 3) f[cnt][i][j] = an[i][j];  work(cnt);++cnt; rep(i, 1, 3) rep(j, 1, 3) f[cnt][i][j] = oo[i][j];  work(cnt);++cnt; rep(i, 1, 3) rep(j, 1, 3) f[cnt][i][j] = eq[i][j];  work(cnt);rep(op, 1, 10){ct = cnt;rep(k, 1, ct){rep(l, 1, 4){rep(i, 1, 3) rep(j, 1, 3) c[i][j] = f[k][i][j];rep(i, 1, 3) rep(j, 1, 3){c[i][j] = f[l][f[k][i][j]][i];check();c[i][j] = f[l][f[k][i][j]][j];check();rep(i, 1, 3) rep(j, 1, 3) c[i][j] = f[k][i][j];}}}//    printf("%d\n", cnt);}//   printf("%d\n", cnt);scanf("%d", &T);while (T--){rep(i, 1, 3){rep(j, 1, 3){char ch[2];scanf("%s", ch);if (ch[0] == 'F') c[i][j] = 1;if (ch[0] == 'U') c[i][j] = 2;if (ch[0] == 'T') c[i][j] = 3;}}judge();}return 0;
}

#include <bits/stdc++.h>using namespace std;#define rep(i, a, b) for (int i(a); i <= (b); ++i)
#define dec(i, a, b)    for (int i(a); i >= (b); --i)
#define MP      make_pair
#define fi      first
#define se      secondtypedef long long LL;const int N = 2e5 + 10;struct node{int x, y;LL val;friend bool operator < (const node &a, const node &b){return a.x < b.x;}
}  d[N];int a[N], b[N];
int n;
int cnt = 0;
int tt;LL c[N];
LL f[N];void update(int x, LL val){for (; x <= N - 2; x += x & -x) c[x] = max(c[x], val);
}LL query(int x){LL ret = 0;for (; x; x -= x & -x) ret = max(ret, c[x]);return ret;
}int main(){scanf("%d", &n);rep(i, 1, n * 2) scanf("%d", a + i), b[i] = a[i];rep(i, 1, n) d[i].val = 0ll + a[i * 2] - a[i * 2 - 1] + 1;sort(b + 1, b + 2 * n + 1);cnt = unique(b + 1, b + 2 * n + 1) - b - 1;rep(i, 1, n * 2) a[i] = lower_bound(b + 1, b + cnt + 1, a[i]) - b;rep(i, 1, n){++tt;d[i].x = a[tt];++tt;d[i].y = a[tt];}rep(i, 1, n){f[i] = query(d[i].x - 1) + d[i].val;update(d[i].y, f[i]);}LL ans = 0;rep(i, 1, N - 2) ans = max(ans, f[i]);printf("%lld\n", ans);return 0;
}