#include<iostream>
#include<cstring>
#include<queue>
#include<set>
#include<map>
#include<algorithm>

using namespace std;
const int N = 3100;
int sum[N];
int main() {
    int n, m;
    while (cin >> n >> m) {
        memset(sum, 0, sizeof(sum));
        for (int i = 0; i < m; i++) {
            int x, y, w;
            cin >> x >> y >> w;
            //获取每个点边权之和
            if (x == y) continue;
            sum[x] += w;
            sum[y] += w;
        }
        
        sort(sum + 1, sum + n + 1);
        
        cout << sum[1] << '\n';
    }
    return 0;
}