1 #include <bits/stdc++.h>
 2 using namespace std;
 3 
 4 const int maxn = 3030;
 5 const int maxm = 100100;
 6 const int inf = 2147483647;
 7 int n, m;
 8 int G[maxn][maxn];
 9 int in[maxn];
10 
11 signed main() {
12     // freopen("in", "r", stdin);
13     int u, v, w;
14     while(~scanf("%d%d",&n,&m)) {
15         memset(G, 0, sizeof(G));
16         memset(in, 0, sizeof(in));
17         for(int i = 0; i < m; i++) {
18             scanf("%d%d%d",&u,&v,&w);
19             if(u != v) {
20                 in[u] += w;
21                 in[v] += w;
22             }
23         }
24         int ret = inf;
25         for(int i = 1; i <= n; i++) {
26             ret = min(ret, in[i]);
27         }
28         printf("%d\n", ret);
29     }
30     return 0;
31 }