#include<iostream>
#include<algorithm>
#include<cmath>
#include<cstring>
using namespace std;
int father[3005];
int m, n, u, v, w;
int find(int x) {
    while (x != father[x])
        x = father[x];
    return x;
}
int main() {
    int x, y, sum[3005];
    while (cin >> n >> m) {
        int j = 1;
        memset(sum, 0, sizeof(sum));
        for (int i = 1; i <= n; i++) {//n个将领
            father[i] = i;
        }
        for (int i = 1; i <= m; i++) {//m个强关系
            cin >> u >> v >> w;
            if (u == v)continue;
            sum[u] += w;
            sum[v] += w;
            x = find(u);
            y = find(v);
            if (x != y) {
                j++;
                father[x] = y;
            }
        }
        if (j == n) {
            sort(sum + 1, sum + n + 1);
            cout << sum[1] << endl;
        }
        else
            cout << 0 << endl;
    }
    return 0;
}