#include <math.h>
#include <bits/stdc++.h>
#include <atcoder/all>
#define rep(i, l, n) for (int i = (l); i < (n); i++)
#define squ(n) (n) * (n)
using namespace std;
using namespace atcoder;
using ll = long long;
using u64 = unsigned long long;
template <class T>	using V = vector<T>;

u64 isqrt(u64 n) {
	u64 ok = 0ll;
	u64 ng = 4000000000ll;
	while (ng - ok > 1ll) {
		u64 mid = (ok + ng) >> 1ll;
		if (mid * mid <= n) {
			ok = mid;
		}
		else {
			ng = mid;
		}
	}
	return ok;
}


int main(void) {
	int n;	cin >> n;
	V<V<ll> > p(n, V<ll>(3));
	rep(i, 0, n) {
		ll x, y, t;	cin >> x >> y >> t;
		p[i] = { x,y,t };
	}

	V<V<u64> > dist(n, V<u64>(n, 1000000000000000000ll));
	rep(i, 0, n) {
		dist[i][i] = 0ll;
	}
	rep(i, 0, n - 1) {
		u64 r1 = (u64)(squ(p[i][0]) + squ(p[i][1]));
		rep(j, i + 1, n) {
			u64 r2 = (u64)(squ(p[j][0]) + squ(p[j][1]));
			u64 d = (u64)(squ(p[i][0] - p[j][0]) + squ(p[i][1] - p[j][1]));
			if (p[i][2] != p[j][2]) {
				d = r1 + r2 - isqrt(4ll * r1 * r2);
			}
			dist[i][j] = dist[j][i] = d;
		}
	}

	rep(k, 0, n) {
		rep(i, 0, n) {
			rep(j, 0, n) {
				dist[i][j] = min(dist[i][j], max(dist[i][k], dist[k][j]));
			}
		}
	}
	u64 ans = dist[0][n - 1];
	cout << ans << endl;

	return 0;
}