#include <iostream>
#include <cstring>
#include <algorithm>

using namespace std;
const int N = 1010,M = 1e5 + 10;
typedef long long LL ;
int p[N];

struct node{
    int a,b,w;
}edge[M];

bool cmp(node &n1,node &n2){
    return n1.w < n2.w;
}

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

int main(){
    int n,m;
    cin >> n >> m;
    for(int i = 1;i <= n;i++) p[i] = i;
    for(int i = 0;i < m;i++){
        int a,b,c;
        cin >> a >> b >> c;
        edge[i] = {a,b,c};
    }

    LL res = 0;
    sort(edge,edge + m,cmp);
    for(int i = 0;i < m;i++){
        auto t = edge[i];
        int a = t.a,b = t.b,c = t.w;
        int pa = find(a),pb = find(b);
        if(pa != pb){
            p[pb] = pa;
            res += (LL)c;
        }
    }

    cout << res << endl;

    return 0;
}