#include <iostream>
#include <cstring>
#include <algorithm>
using namespace std;
const int N = 100010;
int p[N],s[N];
int n,m;
void init()
{
    for(int i = 1;i <= n;i++)p[i] = i; 
}
int find(int x)
{
    if(p[x] != x)p[x] = find(p[x]);
    return p[x];
}

int main()
{
    while(cin>>n>>m)
    {
        init();
        memset (s , 0 ,sizeof s);
        int j = 0;
        while(  m-- )
        {
            int a,b,c;
            cin>>a>>b>>c;
            if(a == b)continue;
                s[a] += c;
                s[b] += c;
            int x = find(a) , y = find(b);
            if(x != y)
            {
                j ++ ;
                p[x] = y;
            }
        }
            if( j == n- 1)
            {
                sort(s+1,s+1+n);
                cout<<s[1]<<endl;
            }
            else 
            cout<<"0"<<endl;
    }
    return 0;
}