#include<map>
#include<set>
#include<cmath>
#include<queue>
#include<stack>
#include<vector>
#include<cstdio>
#include<cassert>
#include<iomanip>
#include<cstdlib>
#include<cstring>
#include<iostream>
#include<algorithm>
#define pi acos(-1)
#define ll long long
#define mod 1000000007
#define ls l,m,rt<<1
#define rs m+1,r,rt<<1|1
#pragma comment(linker, "/STACK:1024000000,1024000000")

using namespace std;

const double g=10.0,eps=1e-9;
const int N=1000+10,maxn=111117,inf=11111;

ll x[N],y[N],r[N];
int par[N];
bool level[N];
vector<int>v[N];
void dfs(int i,bool f)
{
    level[i]=f;
    for(int j=0;j<v[i].size();j++)
        dfs(v[i][j],f^1);
}
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout<<setiosflags(ios::fixed)<<setprecision(9);
    int n;
    cin>>n;
    memset(level,0,sizeof level);
    memset(par,-1,sizeof par);
    for(int i=0;i<n;i++)cin>>x[i]>>y[i]>>r[i];
    for(int i=0;i<n;i++)
    {
        par[i]=-1;
        for(int j=0;j<n;j++)
           if(r[j]>r[i]&&(x[i]-x[j])*(x[i]-x[j])+(y[i]-y[j])*(y[i]-y[j])<=(r[i]-r[j])*(r[i]-r[j]))
             if(par[i]==-1||r[par[i]]>r[j])
                par[i]=j;
        v[par[i]].push_back(i);
    }
    for(int i=0;i<n;i++)
        if(par[i]==-1)
           dfs(i,0);
    double ans=0.00;
    for(int i=0;i<n;i++)
        ans+=pi*r[i]*r[i]*(par[i]==-1||(level[i]==1) ? +1:-1);
    cout<<ans<<endl;
    return 0;
}