#include <iostream>
#include <cstring>
#include <algorithm>
using namespace std;

const int N = 3010,M = 100010;
int p[N];
int d[N];
int n,m;
int find(int x)  // 并查集
{
    if (p[x] != x) p[x] = find(p[x]);
    return p[x];
}

int main()
{
    while(cin>>n>>m)
    {
        for (int i = 1; i <= n; i ++ )p[i]=i;
        memset(d,0,sizeof d);
        int cnt=0;
        while (m -- )
        {
            int a,b,c;
            scanf("%d%d%d", &a, &b,&c);
            if(a==b)continue;
            d[a]+=c;
            d[b]+=c;
            if(find(a)!=find(b))
            {
                p[find(a)]=find(b);
                cnt++;
            }
        }
        if(cnt==n)puts("0");
        else
        {
            sort(d+1,d+1+n);
            printf("%d\n",d[1]);
        }
    }
    return 0;
}