#include<stdio.h>
#include<string.h>
#include<algorithm>
using namespace std;
#define maxm 1000010
#define maxn 3010
#define INF 1000000000
int m,n,u,v,w;
int fa[maxn],sum[maxn];
int find(int x)
{
    if(fa[x]==x) return x;
    return fa[x]=find(fa[x]);
}
int merge(int x,int y)
{
    int fx=find(x);
    int fy=find(y);
    if(fx!=fy)
    {
        fa[fx]=fy;
        return 1;
    }
    return 0;
}
int main()
{
    while(scanf("%d %d",&n,&m)!=EOF)
    {
        for(int i=1;i<=n;i++) fa[i]=i;
        memset(sum,0,sizeof(sum));
        int cnt=n-1;
        for(int i=0;i<m;i++) 
        {
            scanf("%d %d %d",&u,&v,&w);
            if(u==v) continue;
            sum[u]+=w;
            sum[v]+=w;
            if(merge(u,v)) cnt--;
        }
        if(cnt==0)
        {
            sort(sum+1,sum+n+1);
            printf("%d\n",sum[1]);
        } 
        else printf("0\n");
    }
}