#include <iostream>
#include <cstring>
#include <algorithm>
#include<cstdio>
using namespace std;
const int N = 5005;
int n,m;
int p[N],sum[N];

int find(int x)  // 并查集
{
    if (p[x] != x) p[x] = find(p[x]);
    return p[x];
}

int main()
{
    while(scanf("%d%d",&n,&m)!=EOF)
    {
        int ans = 0x3f3f3f3f;
        for(int i=1;i<=n;i++)p[i] = i;
        memset(sum, 0, sizeof sum);
        int j = 1;
        while (m -- ){
            int x,y,t,a,b;
            scanf("%d%d%d", &x, &y,&t);
            if(x==y)continue;
            sum[x]+=t;sum[y]+=t;
            a = find(x),b=find(y);
            if(a!=b)
            {
                j++;p[a]=b;
            }
        }
        if(j==n)
        {
            sort(sum+1,sum+n+1);
            printf("%d\n",sum[1]);
        }else{
            printf("0\n");
        }
    }
}