#include<cstdio>
#include<algorithm>
using namespace std;
#define lb long double
inline int read()
{int x;char c;while((c=getchar())<'0'||c>'9');for(x=c-'0';(c=getchar())>='0'&&c<='9';)x=x*10+c-'0';return x;
}
#define MN 100000
int a[MN+5],b[MN+5];
int main()
{int n=read(),p=read(),t,i;long long cnt=0;lb l,r,mid,sum;for(i=1;i<=n;++i)cnt+=a[i]=read(),b[i]=read();if(cnt<=p)return 0*puts("-1");for(t=100,l=0,r=1e12;--t;){mid=(l+r)/2;for(i=1,sum=0;i<=n;++i)sum+=max((lb)0,a[i]*mid-b[i]);(sum>p*mid?r:l)=mid;}printf("%.10lf",(double)l);
}

#include<cstdio>
#include<cmath>
#include<algorithm>
using namespace std;
inline int read()
{int x,f=1;char c;while((c=getchar())<'0'||c>'9')if(c=='-')f=0;for(x=c-'0';(c=getchar())>='0'&&c<='9';)x=x*10+c-'0';return f?x:-x;
}
#define MN 1000
struct point{double x,y;}p[MN+5];
double dis(point a){return sqrt(a.x*a.x+a.y*a.y);}
point operator-(point a,point b){return (point){a.x-b.x,a.y-b.y};}
double operator*(point a,point b){return a.x*b.y-a.y*b.x;}
int main()
{int n=read(),i,j;double ans=1e18;for(i=0;i<n;++i)p[i].x=read(),p[i].y=read();p[n]=p[0];p[n+1]=p[1];for(i=0;i<n;++i)ans=min(ans,fabs((p[i+1]-p[i])*(p[i+2]-p[i]))/dis(p[i]-p[i+2]));printf("%.10lf",ans/2);
}

#include<cstdio>
#include<vector>
#include<algorithm>
using namespace std;
#define ll long long
char B[1<<26],*S=B,C;int X;
inline int read()
{while((C=*S++)<'0'||C>'9');for(X=C-'0';(C=*S++)>='0'&&C<='9';)X=(X<<3)+(X<<1)+C-'0';return X;
}
#define MN 200000
int gcd(int x,int y){return y?gcd(y,x%y):x;}
vector<int> v[MN+5];
int m,u[MN+5],f[MN+5],r[MN+5],ls=1;
void exgcd(ll x,ll y,ll z,ll&a,ll&b)
{if(!y){a=z/x;b=0;return;}ll aa,bb;exgcd(y,x%y,z,aa,bb);a=-bb;b=-aa-bb*(x/y);
}
void out(int x)
{if(!x)return;out(r[x]);int i;ll a,b;for(i=0;i<v[x].size();++i)exgcd(ls,m,v[x][i],a,b),printf("%d ",(a%m+m)%m),ls=v[x][i];
}
int main()
{fread(B,1,1<<26,stdin);int n,i,j,mx=0;n=read();m=read();for(i=1;i<=n;++i)u[read()]=1;for(i=1;i<m;++i)if(!u[i])v[gcd(i,m)].push_back(i);for(i=1;i<m;++i){if((f[i]+=v[i].size())>f[mx])mx=i;for(j=i;j<m;j+=i)if(f[i]>f[j])f[j]=f[i],r[j]=i;}printf("%d\n",f[mx]+!u[0]);out(mx);if(!u[0])puts("0");
}

#include<cstdio>
char B[1<<26],*S=B,C;int X;
inline int read()
{while((C=*S++)<'0'||C>'9');for(X=C-'0';(C=*S++)>='0'&&C<='9';)X=X*10+C-'0';return X;
}
#define MN 1000000
#define MOD 1000000007
int a[MN+5],p2[MN+5],r2[MN+5],pw[7];
struct data
{int s1,s2,sz;data(int s1=0,int s2=0,int sz=0):s1(s1),s2(s2),sz(sz){}void operator+=(const data&b){s2=(1LL*s2*p2[b.sz]+1LL*b.s2*p2[sz]+2LL*s1*b.s1)%MOD;s1=(1LL*s1*p2[b.sz]+1LL*b.s1*p2[sz])%MOD;sz+=b.sz;}void operator-=(const data&b){sz-=b.sz;s1=((s1-1LL*b.s1*p2[sz])%MOD+MOD)*r2[b.sz]%MOD;s2=((s2-2LL*s1*b.s1-1LL*b.s2*p2[sz])%MOD+MOD)*r2[b.sz]%MOD;}
}s[MN+5];
void solve1(int x,int k,int d,int p)
{if(d>5){if(x!=k)if(p>0)s[x]+=s[k];else s[x]-=s[k];return;}solve1(x,k,d+1,p);if(k%pw[d+1]/pw[d]<9)solve1(x,k+pw[d],d+1,-p);
}
inline int mod(int x){if(x>=MOD)x-=MOD;if(x<0)x+=MOD;return x;}
void solve2(int x,int k,int d,int p)
{if(d>5){if(x!=k)s[x].s2=mod(s[x].s2+p*s[k].s2);return;}solve2(x,k,d+1,p);if(k%pw[d+1]/pw[d]<9)solve2(x,k+pw[d],d+1,-p);
}
int main()
{B[fread(B,1,1<<26,stdin)]=0;int n=read(),i;long long ans=0;while(n--)++a[read()];for(p2[0]=i=1;i<=MN;++i)p2[i]=(p2[i-1]<<1)%MOD;for(r2[0]=i=1;i<=MN;++i)r2[i]=(r2[i-1]*((MOD+1LL)>>1))%MOD;for(pw[0]=i=1;i<7;++i)pw[i]=pw[i-1]*10;for(i=MN;i--;){solve1(i,i,0,-1);while(a[i]--)s[i]+=data(i,1LL*i*i%MOD,1);}for(i=1;i<MN;++i)solve2(i,i,0,1),ans^=1LL*i*s[i].s2;printf("%I64d",ans);
}