#include<cstdio>
#include<cstring>
#include<map>
#include<vector>
#include<algorithm>
using namespace std;
#define mem(a,n) memset(a,n,sizeof(a))
typedef long long LL;
const int N = 3e3 + 5;
LL ans[N];
vector<int>vec;
int main()
{
    int n, m;
    while (~scanf("%d%d", &n, &m))
    {
        LL u, v, w;
        mem(ans, 0);
        for (int i = 0; i < m; i++)
        {
            scanf("%lld%lld%lld", &u, &v, &w);
            if (u == v) continue;////相同时不进行累加
            ans[u] += w;
            ans[v] += w;
        }
        sort(ans + 1, ans + n + 1);
        printf("%lld\n", ans[1]);///最少代价
    }
    return 0;
}