#include<cstdio>

 #include<cstring>

 #include<algorithm>

 #include<cmath>

 #include<iostream>

 using namespace std;

 const int maxn=;

 const double eps=0.0000001;

 long long n;

 double r[maxn]={},x[maxn]={},y[maxn]={};

 struct nod{

     double id,v;

 }e[maxn];

 int tot;

 bool mmp(nod aa,nod bb){

     return aa.id<bb.id;

 }

 double getit(int i){

     tot=;double cnt=;

     for(int j=n;j>i;j--){

         double w=sqrt((x[i]-x[j])*(x[i]-x[j])+(y[i]-y[j])*(y[i]-y[j]));

         if(r[i]+r[j]-w<=||r[i]-r[j]-w>=)continue;

         if(r[j]-r[i]-w>=) return ;

         double z=(r[i]*r[i]-r[j]*r[j]+w*w)/(*w);

         double h=acos(z/r[i])*;

         double xx=x[i]+(x[j]-x[i])/w*z,yy=y[i]+(y[j]-y[i])/w*z;

         double w1=sqrt((x[i]-xx)*(x[i]-xx)+(y[i]+z-yy)*(y[i]+z-yy));

         double h2=asin(w1//z)*;

         if(xx<x[i]){

             if(h2<)h2=-h2;

             else if(h2>) h2=*M_PI-h2; }

         else if (xx>x[i]){if(h2<) h2=*M_PI+h2;}

         h2=h2-h/;

         if(h2<)h2+=*M_PI;

         h=h2+h;

         if(h>*M_PI){

             e[++tot].id=h2;e[tot].v=*M_PI;

             e[++tot].id=;e[tot].v=h-*M_PI;

         }else{e[++tot].id=h2;e[tot].v=h;}

     }

     sort(e+,e++tot,mmp);

     double ll=0.0,rr=0.0;

     for(int j=;j<=tot;j++){

         if(e[j].id-rr<){

             if(e[j].v-rr>){

                 rr=e[j].v;

             }

         }

         else if(e[j].v-rr>){

             cnt+=rr-ll;

             rr=e[j].v;ll=e[j].id;

         }

     }

     cnt+=rr-ll;

     return r[i]*(M_PI*-cnt);

 }

 int main(){

     //freopen("wtf.in","r",stdin);

     scanf("%d",&n);

     for(int i=;i<=n;i++){

         scanf("%lf%lf%lf",&r[i],&x[i],&y[i]);

     }double ans=;

     for(int i=n;i>=;i--){

         ans+=getit(i);

     }printf("%.3f\n",ans);

     return ;

 }