#include<iostream>
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<algorithm>
using namespace std; 
int F[3200],sum[3200];
int find(int p){
    if(F[p]==0)return p;
    return F[p] = find(F[p]);
}
int main(){
    int n,m;
    while(cin>>n>>m){
        int nn = n-1;
        memset(F,0,sizeof(F));
        memset(sum,0,sizeof(sum));
        for(int i = 0;i<m;i++){
            int u,v,w;
            scanf("%d%d%d",&u,&v,&w);
            if(u==v)continue;
            sum[u]+=w;
            sum[v]+=w;
            int a = find(u);
            int b = find(v);
            if(a!=b){
                F[a] = b;
                nn--;
            }
        }
        if(nn==0){
            sort(sum+1,sum+n+1);
            printf("%d\n",sum[1]);
        }else if(nn>0){
            printf("0\n");
        }
    }
    return 0;
}