#include <bits/stdc++.h>
#define int long long
using namespace std;
const int MAXN = 2e5 + 5;
int read(){
    int res = 0, flag = 1;
    char c = getchar();
    for (; c < '0' || c > '9'; c = getchar())
        if (c == '-')
            flag = -1;
    for (; c >= '0' && c <= '9'; c = getchar())
        res = (res << 1) + (res << 3) + (c ^ 48);
    return res * flag;
}
class DisjointSetUnion{
private:
    int fa[MAXN];
    int getFather(int x){
        if (fa[x] == x)
            return x;
        return fa[x] = getFather(fa[x]);
    }
public:
    void init(int n){
        for (int i = 1; i <= n; i++)
            fa[i] = i;
    }
    bool merge(int x, int y){
        x = getFather(x);
        y = getFather(y);
        if (x == y)
            return false;
        fa[y] = x;
        return true;
    }
}DSU;
struct Edge{
    int u, v, w;
    bool operator < (const Edge T) const{
        return w < T.w;
    } 
}e[MAXN];
signed main(){
    int n = read(), m = read();
    DSU.init(n);
    for (int i = 1; i <= m; i++)
        e[i].u = read(), e[i].v = read(), e[i].w = read();
    sort(e + 1, e + m + 1);
    int ans = 0;
    for (int i = 1; i <= m; i++)
        ans += DSU.merge(e[i].u, e[i].v) * e[i].w;
    cout << ans;
    return 0;
}