#include<map>    
#include<stack>    
#include<queue>    
#include<vector>    
#include<math.h>    
#include<stdio.h>    
#include<iostream>    
#include<string.h>    
#include<stdlib.h>    
#include<algorithm>    
using namespace std;    
typedef long long  ll;    
#define inf 100000000000000000    
#define mod 1000000007     
#define  maxn  1000010    
#define  lowbit(x) (x&-x)    
#define  eps 1e-10   
int fa[maxn],a[maxn];
struct node
{
    int x,y;
};
vector<node>q[maxn];
int find(int x)
{
    if(fa[x]==x)
        return x;
    return fa[x]=find(fa[x]);
}
int main()  
{  
    int n,m,i,j,x,y,z;
    while(scanf("%d%d",&n,&m)!=EOF)
    {
        for(i=1;i<=n;i++)
            fa[i]=i;
        for(i=1;i<=m;i++)
        {
            scanf("%d%d%d",&x,&y,&z);
            if(x==y)
                continue;
            node tmp;
            tmp.x=y;tmp.y=z;
            q[x].push_back(tmp);
            tmp.x=x;tmp.y=z;
            q[y].push_back(tmp);
            int t1=find(x),t2=find(y);
            if(t1!=t2)
                fa[t1]=t2;
        }
        int num=0;
        for(i=2;i<=n;i++)
            if(fa[find(i)]!=fa[find(i-1)])
                num++;
        if(num>0)
            printf("0\n");
        else
        {
            int ans=1000000000;
            for(i=1;i<=n;i++)
            {
                int t=0;
                for(j=0;j<q[i].size();j++)
                    t+=q[i][j].y;
                ans=min(ans,t);
            }
            printf("%d\n",ans);
        }
        for(i=1;i<=n;i++)
            q[i].clear();
    }
    return 0;  
}