#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<iostream>
#include<algorithm>
 
using namespace std;
 
 
const int MAX = 3005;
int pre[MAX];
int sum[MAX];
int flag;
 
 
int find (int x){
    int r =x;
    if(pre[r]!=r){
        pre[r]=find(pre[r]);
    }
    return pre[r];
}
 
 
void join (int x,int y){
    int fx=find(x);
    int fy=find(y);
 
    if(fx==fy){
        flag=1;
        return;
    }
    pre[fx]=pre[fy];
    return ;
}
 
 
void init(int n){
    int i;
 
    for(i=1;i<=n;++i)pre[i] = i;
    flag = 0;
}
 
 
int main (){
    int m,n;
    while(scanf("%d%d",&n,&m)!=EOF){
 
        int i,j;
        int a,b,c;
        int fa,fb;
        int cnt = n-1;
 
        memset(sum,0,sizeof(sum));
 
        init(n);
        for(i=0;i<m;i++){
            scanf("%d%d%d",&a,&b,&c);
 
            if(a==b)
                continue;
            sum[a]+=c;
            sum[b]+=c;
 
            int cs1=find(a);
            int cs2=find(b);
            if(cs1!=cs2){
                cnt--;
                join(a,b);
            }
        }
 
        if(cnt){
            printf("0\n");
        }
        else{
            sort(sum+1,sum+n+1);
            printf("%d\n",sum[1]);
        }
    }
    return 0;
}