#include <iostream>
#include <stdio.h>
#include<bits/stdc++.h>
using namespace std;

const int MAX_M=10003;
const int MAX_N=3002;
int n,m;
int cost[MAX_N];
struct relation
{
    int u,v,w;
}R[MAX_M];
int main(){
    //freopen("in.txt","r",stdin);
    while(~scanf("%d%d",&n,&m)){
        int result;
        memset(cost,0,sizeof(cost));
        for(int i=1;i<=m;i++){
            cin>>R[i].u>>R[i].v>>R[i].w;
            if(R[i].u!=R[i].v){
                cost[R[i].u]+=R[i].w;
                cost[R[i].v]+=R[i].w;
            }
        }

        result=cost[1];
        for(int i=2;i<=n;i++){
            if(result>cost[i]) result=cost[i];
        }
        cout<<result<<endl;
    }
}