#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;
}