#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <ctime>
#include <cstdlib>
#include <queue>
#include <stack>
#include <vector>
#include <set>
#define maxn 3010
#define maxm 200010

using namespace std;

int n, m;
int cost[maxn];
int p[maxn], vis[maxn];

int find(int x)
{
    if (p[x] != x) return p[x] = find(p[x]);
    return x;
}

int main()
{
    while (cin >> n >> m)
    {
        memset(vis, 0, sizeof vis);
        memset(cost, 0, sizeof cost);
        for (int i = 1; i <= n; i ++ ) p[i] = i;
        for (int i = 1; i <= m; i ++ )
        {
            int a, b, c;
            scanf("%d%d%d", &a, &b, &c);
            if (a == b) continue;
            cost[a] += c, cost[b] += c;
            int pa = find(a), pb = find(b);
            p[pa] = pb;
        }
        
        for (int i = 1; i <= n; i ++ )
        {
            int pi = find(i);
            vis[pi] = 1;
        }
        
        int flag = 0;
        for (int i = 1; i <= n; i ++ ) if (vis[i]) flag ++ ;
        
        if (flag != 1) puts("0");
        else
        {
            int res = 1e9;
            for (int i = 1; i <= n; i ++ ) res = min(res, cost[i]);
            printf("%d\n", res);
        }
    }
    
    return 0;
}