#include<bits/stdc++.h>
using namespace std;
const int MAX_N = 1e5+10;
int n,m,u[MAX_N],v[MAX_N],sum[MAX_N];
int father[MAX_N];
int get(int x){
    while(x!=father[x]){
        x = father[x];
    }
    return x;
}

int main(){
    ios::sync_with_stdio(0);
    while(cin>>n>>m){
        int ans = 0;
        memset(sum,0,sizeof(sum));
        for(int i=1;i<=n;i++){
            father[i] = i;
        }
        for(int i=1;i<=m;i++){
            int a,b,w;
            cin>>a>>b>>w;
            if(a==b){
                continue;
            }
            sum[a] += w;
            sum[b] += w;
            a = get(a);
            b = get(b);
            if(a!=b){
                ans++;
                father[a] = b;
            }
        }
        if(ans==n-1){
            sort(sum+1,sum+n+1);
            cout<<sum[1]<<endl;
            continue;
        }
        cout<<"0\n";
        
    }
    return 0;
}