/**
 * Author: Fau
 * Time: 2021-07-28 17:27
**/

#include <bits/stdc++.h>
#define rep(i, n) for (int i = 1; i <= (n); ++i)
#define debug(a) cout << #a << " = " << a << endl
using namespace std;
typedef long long ll;
const int N = 3E3 + 10;
int n, m;

int p[N], cost[N];
int find(int x) { return x == p[x] ? x : p[x] = find(p[x]); }
int main()
{
#ifndef ONLINE_JUDGE
    freopen("/Users/Fau/Documents/Fau/project/Clion Program/TEXT/in.txt", "r", stdin);
    freopen("/Users/Fau/Documents/Fau/project/Clion Program/TEXT/out.txt", "w", stdout);
#endif
//------------------------------------------------------------CODE BEGIN------------------------------------------------------------

    while (~scanf("%d %d", &n, &m)) {
        iota(p + 1, p + 1 + n, 1);
        fill(cost + 1, cost + 1 + n, 0);

        int cou = 1;
        rep(i, m) {
            int a, b, c; scanf("%d %d %d", &a, &b, &c);
            if (a == b) continue;
            
            cost[a] += c, cost[b] += c;
            a = find(a), b = find(b);

            if (a != b) p[b] = a, cou++;
        }

        int fmin = 0x3f3f3f3f;
        rep(i, n) fmin = min(fmin, cost[i]);

        printf("%d\n", cou == n ? fmin : 0);
    }

//-------------------------------------------------------------CODE END-------------------------------------------------------------
#ifndef ONLINE_JUDGE
    fclose(stdout);
    system("/Users/Fau/Documents/Fau/project/Clion\\ Program/compare_Fau");
#endif
    return 0;
}