自闭的萌新+1

#include<bits/stdc++.h>

using namespace std;

#define Reimu inline void
#define Marisa inline int

namespace FastInput {
	template<typename Ty>
	inline Ty read() {
		Ty x = 0;
		int f = 0;
		char c = getchar();
		for (; !isdigit(c); c = getchar()) f |= c == '-';
		for (; isdigit(c); c = getchar()) x = (x << 1) + (x << 3) + (c & 15);
		return f ? -x : x;
	}

	template<>
	inline double read() {
		double x = 0;
		int f = 0;
		char c = getchar();
		for (; !isdigit(c); c = getchar()) f |= c == '-';
		for (; isdigit(c); c = getchar()) x = x * 10 + (c & 15);
		if (c == '.') {
			double e = 1;
			for (c = getchar(); isdigit(c); c = getchar()) x += (c & 15) * (e *= .1);
		}
		return f ? -x : x;
	}

	template<>
	inline char read() {
		char c = getchar();
		while (!isgraph(c)) c = getchar();
		return c;
	}

	template<>
	inline string read() {
		string s = "";
		char c = getchar();
		for (; !isgraph(c); c = getchar());
		for (; isgraph(c); c = getchar()) s += c;
		return s;
	}

	template<typename Ty>
	Reimu read(Ty &x) {
		x = read<Ty>();
	}

	template<typename Ty, typename...Arr>
	Reimu read(Ty &x, Arr &...arr) {
		read(x);
		read(arr...);
	}
}
using namespace FastInput;

namespace Mod {
    const int mod = 19260817;
    Marisa add(int x, int y) {
        return (x += y) < mod ? x < 0 ? x + mod : x : x - mod;
    }
    Marisa Add(int&x, int y) {
        return (x += y) < mod ? x < 0 ? (x += mod) : x : (x -= mod);
    }
    Marisa mul(int x, int y) {
        return 1LL * x * y % mod;
    }
    Marisa Mul(int&x, int y) {
        return x = 1LL * x * y % mod;
    }
    Marisa qpow(int x, int y) {
        int res = 1;
        for (; y; y >>= 1) {
            if (y & 1) Mul(res, x);
            Mul(x, x);
        }
        return res;
    }
    Marisa inv(int x) {
        return qpow(x, mod - 2);
    }
}
using namespace Mod;

typedef pair<int, int> Pii;
typedef pair<int, Pii> Piii;
#define fi first
#define se second
#define mp make_pair

const int N = 300010;

int n;
int inc[N], sz[N];
Piii e[N];
vector<int> g[N];

Reimu getCir(int x, int fa) {
	inc[x] = 1;
	try {
		for (auto y: g[x]) {
			if (y == fa) continue;
			if (inc[y]) throw y;
			getCir(y, x);
		}
	} catch(int v) {
		if (!v) throw inc[x] = 0;
		if (v == x) throw 0;
		throw v;
	}
}

Reimu dfs(int x, int fa) {
	sz[x] = 1;
	for (auto y: g[x]) {
		if (y == fa || inc[y]) continue;
		dfs(y, x);
		sz[x] += sz[y];
	}
}

int main() {
	read(n);
	for (int i = 1; i <= n; ++i) {
		int x = e[i].se.fi = read<int>(), y = e[i].se.se = read<int>();
		read(e[i].fi);
		g[x].emplace_back(y);
		g[y].emplace_back(x);
	}
	try {
		getCir(1, 0);
	} catch(int) {}
	int t = 0, c = 0, ans = 0, inv2 = inv(2);
	for (int i = 1; i <= n; ++i) {
		if (inc[i]) {
			dfs(i, 0);
			Add(t, mul(sz[i], sz[i]));
			++c;
		}
	}
	c = add(add(mul(n, n), -t), add(mul(n, 2), -c));
	for (int i = 1; i <= n; ++i) {
		int v = e[i].fi, x = e[i].se.fi, y = e[i].se.se;
		if (inc[x] && inc[y]) Add(ans, mul(mul(v, c), inv2));
		else {
			int l = min(sz[x], sz[y]), r = n - l;
			Add(ans, mul(mul(v, mul(l, r)), 2));
		}
	}
	printf("%d", mul(ans, inv(mul(n, n))));
	return 0;
}