#include <iostream>

#include <queue>

#define REP(i,a,n) for(int i=a;i<=n;++i)

using namespace std;

typedef long long ll;

ll gcd(ll a,ll b) {return b?gcd(b,a%b):a;}

const int N = 1e6+10;

int n, dp[N][3];

struct _ {int to,w;};

vector<_> g[N];

ll ans;

void dfs(int x, int fa, int d) {

	for (int i=0; i<g[x].size(); ++i) {

		int y = g[x][i].to;

		if (y==fa) continue;

		dfs(y,x,(d+g[x][i].w)%3);

		ans += 2ll*dp[y][d];

		REP(i,0,2) ans += 2ll*dp[x][i]*dp[y][(2*d-i+3)%3];

		REP(i,0,2) dp[x][i] += dp[y][i];

	}

	++dp[x][d],++ans;

}

int main() {

	scanf("%d", &n);

	REP(i,2,n) {

		int u, v, w;

		scanf("%d%d%d", &u, &v, &w);

		w %= 3;

		g[u].push_back({v,w});

		g[v].push_back({u,w});

	}

	dfs(1,0,0);

	ll x = ans, y = (ll)n*n, z = gcd(x,y);

	x /= z, y /= z;

	printf("%lld/%lld\n", x,y);

}