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

class UnionFind{
    private:
    vector<int> par,siz;
    public:
    UnionFind(int N){
        par.resize(N,-1);
        siz.resize(N,1);
    }
 
    int root(int x){ //連結成分の代表頂点を返す.
        if(par.at(x) == -1) return x;
        else return par.at(x) = root(par.at(x));
    }
    bool unite(int u, int v){ //u,vを連結する 連結してた->false,した->trueを返す.
        u = root(u),v = root(v);
        if(u == v) return false;
 
        if(siz.at(u) < siz.at(v)) swap(u,v); //Union by size.
        par.at(v) = u;
        siz.at(u) += siz.at(v);
        return true;
    }
    bool issame(int u, int v){ //同じ連結成分ならtrue.
        if(root(u) == root(v)) return true;
        else return false;
    }
    int size(int pos){return siz.at(root(pos));} //posの連結成分の大きさを返す.
};

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    int N,M; cin >> N >> M;
    vector<vector<pair<int,int>>> UV(6);
    while(M--){
        int u,v,c; cin >> u >> v >> c; u--; v--; c--;
        UV.at(c).push_back({u,v});
    }

    UnionFind Z(N);
    vector<int> C(6);
    for(int i=0; i<6; i++){
        for(auto [u,v] : UV.at(i)) if(Z.issame(u,v) == false) Z.unite(u,v),C.at(i)++;
    } 

    map<vector<int>,double> memo;
    memo[{0,0,0,0,0,0}] = 0;
    auto solve = [&](auto solve,vector<int> &A) -> double {
        if(memo.count(A)) return memo[A];
        int zero = 0,use = -1;
        double ret = 0;
        for(int i=0; i<6; i++){
            if(A.at(i)) use = i;
            if(use == -1){zero++; continue;}

            A.at(use)--; 
            ret += solve(solve,A);
            A.at(use)++; 
        }
        ret /= 6-zero; ret += 6/(6.0-zero);
        memo[A] = ret;
        return ret;
    };
    cout << fixed << setprecision(20) << solve(solve,C) << endl;
}