#include<bits/stdc++.h>
using namespace std;

#include<atcoder/all>
using namespace atcoder;
using mint=atcoder::modint998244353;

#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")

#define rep(i,n) for(int i=0;i<(n);i++)
#define rng(i,l,r) for(int i=(l);i<(r);i++)
#define rrep(i,n) for(int i=(n)-1;i>=0;i--)
#define rrng(i,l,r) for(int i=(r)-1;i>=(l);i--)
#define ALL(x) (x).begin(),(x).end()

// #define int long long
#define fi first
#define se second

struct fast_io{fast_io(){cin.tie(nullptr)->sync_with_stdio(false);}}_;

signed main(){
	int N,M;cin>>N>>M;

	vector<array<int,3>> ve(M);
	for(auto&&[u,v,c]:ve)cin>>u>>v>>c,u--,v--,c--;

	vector<vector<pair<int,int>>> ve2(6);
	for(auto&&[u,v,c]:ve)ve2[c].push_back({u,v});
	array<int,6> cnt;
	rep(i,6)cnt[i]=0;
	dsu d(N);
	rep(i,6){
		for(auto&&[u,v]:ve2[i]){
			if(d.same(u,v))continue;
			cnt[i]++;
			d.merge(u,v);
		}
	}

	// cout<<"cnt : ";for(auto&&e:cnt)cout<<e<<" ";cout<<endl;

	map<array<int,6>,double> dp;
	
	auto dfs=[&](auto dfs,array<int,6> ar)->double {
		
		if(dp.count(ar))return dp[ar];
		if(*max_element(ar.begin(),ar.end())==0)return 0;
		// cout<<"ar : ";for(auto&&e:ar)cout<<e<<" ";cout<<endl;

		double sm=0;
		int sub=0;
		rep(i,6){
			array<int,6> ar2=ar;
			bool flg=0;
			rrep(j,i+1)if(ar2[j]){ar2[j]--;flg=1;break;}
			if(flg)sm+=dfs(dfs,ar2);
			else sub++;
		}
		sm/=(6-sub);
		sm+=6/double(6-sub);
		return dp[ar]=sm;
	};

	cout<<fixed<<setprecision(20)<<dfs(dfs,cnt)<<endl;
}