#include <iostream>
#include <fstream>
#include <vector>
#include <random>
#include <algorithm>
#include <queue>
using namespace std;

typedef pair<int,int> PII;
typedef vector<int> VI;
typedef vector<pair<int,int>> VII;

template<typename T>
void print(vector<T> sez) {
    for (T x : sez) cout << x << " ";
    cout << endl;
}

class DisjointSet {  // union-find
public:
    vector<int> parent, size;
    DisjointSet(int n) {
        parent = vector<int>(n);
        size = vector<int>(n);
        for (int i=0;i<n;i++) {
            parent[i] = i;
            size[i] = 1;
        }
    }

    int root(int x) {
        if (parent[x] == x) return x;
        int r = root(parent[x]);
        parent[x] = r;  // path-compression
        return r;
    }

    void join(int x, int y) {
        x=root(x); y=root(y);
        if (x==y) return;
        if (size[x]>size[y]) swap(x,y);  // x smaller
        parent[x]=y;
        size[y]+=size[x];
    }
};

bool cmpW(VI e1, VI e2) { return e1[2] < e2[2]; }

int Kruskal(int n, vector<VI> &edges) {
    int cost=0;
    DisjointSet ds(n);
    sort(edges.begin(),edges.end(),cmpW);
    for (VI e : edges) {
        int a=e[0], b=e[1], w=e[2];
        if (ds.root(a)==ds.root(b)) continue;
        cost+=w;
        ds.join(a,b);
    }
    return cost;
}

int main() {
    ifstream fin("mst.txt");
    int n,m;
    fin >> n >> m;
    vector<VI> edges;
    for (int i=0;i<m;i++) {
        int a,b,w;
        fin >> a >> b >> w;
        edges.push_back({a,b,w});
    }
    // 37
    cout << Kruskal(n,edges) << endl;
    return 0;
}