1 #include <bits/stdc++.h>
 2 using namespace std;
 3
 4 #define ll long long
 5 #define INFLL 0x3f3f3f3f3f3f3f3f
 6 #define N 110
 7 int n, m;
 8 int dist[20][20];
 9 ll f[1 << 15][15];
10
11 vector <int> vec[1 << 15];
12 int sze[1 << 15];
13
14 int main()
15 {
16     while (scanf("%d%d", &n, &m) != EOF)
17     {
18         memset(dist, -1, sizeof dist);
19         memset(f, -1, sizeof f);
20         for (int S = 0, len = (1 << n); S < len; ++S)
21         {
22             for (int i = 0; i < n; ++i) if ((S >> i) & 1)
23                 vec[S].push_back(i + 1);
24             sze[S] = vec[S].size();
25             if (sze[S] == 1)
26                 f[S][*vec[S].begin()] = 0;
27         }
28         for (int i = 1, u, v, w; i <= m; ++i)
29         {
30             scanf("%d%d%d", &u, &v, &w);
31             dist[u][v] = dist[v][u] = w;
32         }
33         ll res = 0;
34         for (int S = 1, len = (1 << n); S < len; ++S)
35         {
36             for (auto u : vec[S])
37             {
38                 for (int T = (S - 1) & S; T != 0; T = (T - 1) & S) // 枚举子集
39                 {
40                     for (auto v : vec[T])
41                     {
42                         if (dist[u][v] == -1 || f[T][v] == -1 || f[S - T][u] == -1) continue;
43                         f[S][u] = max(f[S][u], f[T][v] + f[S - T][u] + 1ll * dist[u][v] * sze[T] * (n - sze[T]));
44                     }
45                 }
46                 if (S == (1 << n) - 1)res = max(res, f[S][u]);
47             }
48         }
49         printf("%lld\n", res);
50     }
51     return 0;
52 }