#include<bits/stdc++.h>
namespace {
#pragma GCC diagnostic ignored "-Wunused-function"
#include<atcoder/all>
#pragma GCC diagnostic warning "-Wunused-function"
using namespace std;
using namespace atcoder;
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
#define rrep(i,n) for(int i = (int)(n) - 1; i >= 0; i--)
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
template<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } else return false; }
template<class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return true; } else return false; }
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;

map<array<char, 6>, double> memo;

double dfs(array<char, 6> a) {
  auto [it, inserted] = memo.emplace(a, 0.0);
  if (!inserted) return it->second;
  int i = 0;
  while (i < 6 && a[i] == 0) i++;
  if (i == 6) return 0.0;
  double res = 0, res_last = 0.0;
  int bad = i;
  while (i < 6) {
    if (a[i]) {
      a[i]--;
      res_last = dfs(a);
      a[i]++;
    }
    res += res_last;
    i++;
  }
  return it->second = (6 + res) / (6 - bad);
}

} int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, m;
  cin >> n >> m;
  vector<P> es[6];
  rep(_, m) {
    int u, v, c;
    cin >> u >> v >> c;
    u--, v--, c--;
    es[c].emplace_back(u, v);
  }
  array<char, 6> a{};
  dsu uf(n);
  rep(i, 6) {
    for (auto [u, v] : es[i]) {
      if (!uf.same(u, v)) uf.merge(u, v), a[i]++;
    }
  }
  auto ans = dfs(a);
  cout << fixed << setprecision(12) << ans << '\n';
}