#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cmath>
using namespace std;
typedef double db;
int const xn=1005,inf=2005;
db const eps=1e-8;
int n;
bool tmp[xn];
struct N{int x,y,r;}c[xn];
struct S{db l,r;}seg[xn];
int rd()
{int ret=0,f=1; char ch=getchar();while(ch<'0'||ch>'9'){if(ch=='-')f=0; ch=getchar();}while(ch>='0'&&ch<='9')ret=ret*10+ch-'0',ch=getchar();return f?ret:-ret;
}
int dmp(db x)
{if(fabs(x)<eps)return 0;else if(x>eps)return 1;else return -1;
}
db sqr(db x){return x*x;}
bool cmp(S a,S b){return dmp(a.l-b.l)<0||(dmp(a.l-b.l)==0&&dmp(a.r-b.r)<0);}
bool cmp2(N a,N b){return a.r<b.r;}
db maxx(db x,db y){if(dmp(x-y)<0)return y; return x;}
bool in(int a,int b){return sqr(c[a].x-c[b].x)+sqr(c[a].y-c[b].y)<=sqr(c[a].r-c[b].r);}
void init()
{sort(c+1,c+n+1,cmp2);for(int i=1;i<=n;i++){for(int j=i+1;j<=n;j++)if(in(i,j)){tmp[i]=1; break;}}int tot=0;for(int i=1;i<=n;i++)if(!tmp[i])c[++tot]=c[i];n=tot;
}
db f(db x)
{int cnt=0;for(int i=1;i<=n;i++){if(dmp(fabs(c[i].x-x)-c[i].r)>0)continue;db dis=sqrt(sqr(c[i].r)-sqr(x-c[i].x));seg[++cnt].l=c[i].y-dis; seg[cnt].r=c[i].y+dis;}sort(seg+1,seg+cnt+1,cmp);db ret=0,r=-inf;for(int i=1;i<=cnt;i++){if(dmp(seg[i].l-r)>0)ret+=seg[i].r-seg[i].l,r=seg[i].r;else if(dmp(seg[i].r-r)>0)ret+=seg[i].r-r,r=seg[i].r;}return ret;
}
db simp(db l,db r){return (r-l)/6*(f(l)+4*f((l+r)/2)+f(r));}
db asr(db l,db r,db eps,db lst)
{db mid=(l+r)/2;db ls=simp(l,mid),rs=simp(mid,r);if(fabs(ls+rs-lst)<=15*eps)return ls+rs+(ls+rs-lst)/15;return asr(l,mid,eps/2,ls)+asr(mid,r,eps/2,rs);
}
db asr(db l,db r,db lst)
{db mid=(l+r)/2;db ls=simp(l,mid),rs=simp(mid,r);if(fabs(ls+rs-lst)<=eps)return ls+rs;return asr(l,mid,ls)+asr(mid,r,rs);
}
int main()
{n=rd(); int L=inf,R=-inf;for(int i=1;i<=n;i++)c[i].x=rd(),c[i].y=rd(),c[i].r=rd(),L=min(L,c[i].x-c[i].r),R=max(R,c[i].x+c[i].r);init();//printf("%.3f\n",asr(L,R,eps,simp(L,R)));//printf("%.3f\n",asr(L,R,simp(L,R)));printf("%.3f\n",asr(-inf,inf,simp(-inf,inf)));//printf("%.3f\n",asr(-inf,inf,eps,simp(-inf,inf)));return 0;
}

#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cmath>
using namespace std;
typedef double db;
int const xn=1005,inf=2005;
db const eps=1e-13;
int n,st,ed,xl[xn],xr[xn];
bool tmp[xn];
struct N{int x,y,r;bool operator < (const N &b) const{return r<b.r;}
}c[xn];
struct S{db l,r;bool operator < (const S &b) const{return l<b.l;}
}seg[xn];
int rd()
{int ret=0,f=1; char ch=getchar();while(ch<'0'||ch>'9'){if(ch=='-')f=0; ch=getchar();}while(ch>='0'&&ch<='9')ret=ret*10+ch-'0',ch=getchar();return f?ret:-ret;
}
db sqr(db x){return x*x;}
//bool cmp(S a,S b){return a.l<b.l;}
//bool cmp2(N a,N b){return a.r<b.r;}
bool cmp3(N a,N b){return a.x-a.r<b.x-b.r;}
bool in(int a,int b){return sqr(c[a].x-c[b].x)+sqr(c[a].y-c[b].y)<=sqr(c[a].r-c[b].r);}
void init()
{sort(c+1,c+n+1);//cmp2for(int i=1;i<=n;i++){for(int j=i+1;j<=n;j++)if(in(i,j)){tmp[i]=1; break;}}int tot=0;for(int i=1;i<=n;i++)if(!tmp[i])c[++tot]=c[i];n=tot;sort(c+1,c+n+1,cmp3);//
}
db f(db x)
{int cnt=0;for(int i=st;i<=ed;i++){if(xl[i]>=x||xr[i]<=x)continue;db dis=sqrt(c[i].r-sqr(x-c[i].x));//(sqr)seg[++cnt].l=c[i].y-dis; seg[cnt].r=c[i].y+dis;}sort(seg+1,seg+cnt+1);//cmpdb ret=0,r=-inf;for(int i=1,j;i<=cnt;i=j){r=seg[i].r;for(j=i+1;j<=cnt&&seg[j].l<=r;j++)if(r<seg[j].r)r=seg[j].r;ret+=r-seg[i].l; }return ret;
}
db simp(db len,db fl,db fr,db fm){return len/6*(fl+4*fm+fr);}
db asr(db l,db r,db mid,db fl,db fr,db fm,db lst)
{db lmid=(l+mid)/2,flm=f(lmid),rmid=(mid+r)/2,frm=f(rmid);db ls=simp(mid-l,fl,fm,flm),rs=simp(r-mid,fm,fr,frm);if(fabs(ls+rs-lst)<=eps)return ls+rs;return asr(l,mid,lmid,fl,fm,flm,ls)+asr(mid,r,rmid,fm,fr,frm,rs);
}
int main()
{n=rd();for(int i=1;i<=n;i++)c[i].x=rd(),c[i].y=rd(),c[i].r=rd();init(); db ans=0;for(int i=1;i<=n;i++)xl[i]=c[i].x-c[i].r,xr[i]=c[i].x+c[i].r,c[i].r=c[i].r*c[i].r;for(int i=1,j;i<=n;i=j){int l=xl[i],r=xr[i];for(j=i+1;xl[j]<=r&&j<=n;j++)if(xr[j]>r)r=xr[j];st=i; ed=j-1; db mid=(l+r)/2;db fl=f(l),fm=f(mid),fr=f(r);ans+=asr(l,r,mid,fl,fr,fm,simp(r-l,fl,fr,fm));}printf("%.3f\n",ans);return 0;
}