#include <bits/stdc++.h>
using namespace std;
int fa[3005], sizes[3005];
int cnt;
int get(int x) {
    return x == fa[x] ? x : get(fa[x]);
}
void merge(int _u, int _v) {
    int u = get(_u), v = get(_v);
    if (u != v) {
        fa[u] = v;
        ++cnt;
    }
}
int main() {
    int n, m;
    while (cin >> n >> m) {
        memset(sizes, 0, sizeof sizes);
        cnt = 1;
        for (int i = 1; i <= n; ++i) {
            fa[i] = i;
        }
        for (int i = 1; i <= m; ++i) {
            int u, v, w;
            cin >> u >> v >> w;
            if (u == v) {
                continue;
            } 
            sizes[u] += w;
            sizes[v] += w;
            merge(u, v);
        }
        if (cnt == n) {
            int minn = sizes[1];
            for (int i = 2; i <= n; ++i) {
                minn = min(minn, sizes[i]);
            }
            cout << minn << '\n';
        } else {
            cout << 0 << '\n';
        }
    }    
    return 0;    
}