#include <cstdio>
#include <iostream>
#include <cmath>

#define N int(1e5 + 5)

using namespace std;

typedef long long LL;

int n, x[N], y[N], r[N];
bool in[N];

LL sqr(LL a) {
    return a * a;
}

int main() {
    freopen("circles.in", "r", stdin);
    freopen("circles.out", "w", stdout);

    scanf("%d ", &n);

    for (int i = 0; i < n; i++)
        scanf("%d %d %d ", x + i, y + i, r + i);

    if (n <= 5000) {
        for (int i = 0; i < n; i++)
            for (int j = 0; j < n; j++) {
                if (i == j) continue;

                if (sqr(r[i] - r[j]) >= sqr(x[i] - x[j]) + sqr(y[i] - y[j]) && r[i] <= r[j])
                    in[i]++;
            }
    }

    long double res = 0;
    for (int i = 0; i < n; i++)
        if (!in[i])
            res += M_PI * sqr(r[i]);

    cout.precision(9);
    cout << fixed << res << endl;

    return 0;
}