#include <iostream>
#include <fstream>
#include <vector>
#include <set>
#include <map>
#include <string>
#include <cmath>
#include <cassert>
#include <ctime>
#include <algorithm>
#include <queue>
#include <memory.h>
#include <stack>

using namespace std;

#define pb push_back
#define mp make_pair
#define fir first
#define fi first
#define sec second
#define y1 botva23
typedef long long int64;
typedef long double ld;

const int inf=2000000000;
const ld eps=1e-07;
const ld pi = 3.1415926535897932384626;

int n;
pair <int64, pair <int64, int64> > a[110000];
bool used[110000];

bool in(int x, int y) {
	if ((a[x].first * a[x].first) >
		((a[x].second.first - a[y].second.first) * (a[x].second.first - a[y].second.first)
		+ (a[x].second.second - a[y].second.second) * (a[x].second.second - a[y].second.second)))
	return true;
	return false;
}

int main(){
	freopen("circles.in","r",stdin);
	freopen("circles.out","w",stdout);
	scanf("%d", &n);
	for (int i = 0; i < n; ++i) {
		int x, y, r;
		scanf("%d %d %d", &x, &y, &r);
		a[i].first = r;
		a[i].second.first = x;
		a[i].second.second = y;
	}
	sort(a, a + n);
	reverse(a, a + n);
	for (int i = 1; i < n; ++i)
		if (a[i] == a[i - 1])
			used[i] = true;
	for (int i = 1; i < n; ++i)
		if (in(i - 1, i))
			used[i] = true;
	ld ans = 0;
	for (int i = 0; i < n; ++i)
		if (!used[i]) {
			ans += pi * ld(a[i].first) * ld(a[i].first);
			for (int j = i + 1; j < n; ++j)
				if (!used[j] && in(i, j))
					used[j] = true;
		}
	cout.precision(10);
	cout << fixed << ans << endl;
	return 0;
}