#include <stdio.h>
#include <string.h>

const int MAXN = 1024;
const int MAXLEN = 1000;
int g[MAXN][MAXN];
int used[MAXN];

int min(int a, int b) {
    if (a <= b)
        return a;
    return b;
}

int main() {
    int n, m;
    scanf("%d %d", &n, &m);


    for (int i = 0; i < n; ++i) {
        int a, b, k;
        scanf("%d %d %d", &a, &b, &k);
        g[a][b] = k;
        g[b][a] = k;
    }
    int mine[MAXN];
    for (int i = 0; i < n; ++i) {
        mine[i] = MAXLEN;
        used[i] = 0;
    }

    int ans = 0;
    mine[0] = 0;
    for (int i = 0; i < n; ++i)
    {
        int min_dist = MAXLEN, u;
        for (int j = 0; j < n; ++j)
            if (!used[j] && mine[j] < min_dist)
            {
                min_dist = mine[j];
                u = j;
            }
        ans += min_dist;
        used[u] = 1;
        for (int v = 0; v < n; ++v)
            if (g[u][v])
                mine[v] = min(mine[v], g[u][v]);
    }

    printf("%d", ans);

    return 0;
}
/*
5 5
0 1 5
0 2 10
1 3 4
1 4 10
2 4 6
 */