#include<iostream>
#include<stdio.h>
#include<string.h>
#include<algorithm>
#define N 100005
#define MS(a,b) memset(a,b,sizeof(a))
#define maxn 0x7fffffff
using namespace std;
int fa[4000];
int findx(int x)
{
    if(fa[x]!=x)
    fa[x]=findx(fa[x]);
    return fa[x];
}
void Union(int x,int y)
{
    int tx,ty;
    tx=findx(x);ty=findx(y);
     if(tx!=ty)
        fa[tx]=ty;
}
int main()
{
   int n,m,i,j,a,b,w[N],ans[4000],sum,s;

     while(~scanf("%d %d",&n,&m))
     {
         for(i=1;i<=n;i++)
                fa[i]=i;
                MS(ans,0);
         for(i=0;i<m;i++)
            {
                scanf("%d %d %d",&a,&b,&w[i]);
                if(a==b)continue;
                   ans[a]+=w[i];ans[b]+=w[i];
                   Union(a,b);
            }
            sum=0;
        for(i=1;i<=n;i++)
            if(fa[i]==i)
              sum++;
              s=maxn;
        if(sum!=1)
           cout<<0<<endl;
        else
         {
           for(i=1;i<=n;i++)
             s=min(s,ans[i]);
             cout<<s<<endl;
         }
     }
    return 0;
}