#include<bits/stdc++.h>
using namespace std;

const int N = 100010;
int f[N], sum[N], cnt;
int n, m;

void init()
{
    for(int i = 0; i <= n; i ++)
    {
        f[i] = i;
    }
    memset(sum, 0, sizeof sum);
    cnt = 0;
}

int found(int x)
{
    if(x != f[x]) f[x] = found(f[x]);
    return f[x];
}

int main()
{
    while(cin >> n >> m)
    {
        init();

        while(m --)
        {
            int a, b, c;
            cin >> a >> b >> c;

            if(a == b) continue;

            sum[a] += c;
            sum[b] += c;

            int x = found(a);
            int y = found(b); 
            if(x != y)
            {
                f[y] = x;
                cnt ++;
            }
        }

        int ans = 0, temp = 0x3f3f3f3f;
        if(cnt == n - 1)
        {
            sort(sum + 1, sum + 1 + n);
            cout << sum[1] << endl;
        }
        else puts("0");
    }
    return 0;
}