<iostream>
#include <math.h>
#include <queue>
#include <vector>
#define N 101
using namespace std;
int n, m;
vector <vector <int> > graph;
vector <vector <int> > graph2;
vector <int> way;
vector <int> isAdded;

struct EL {
    int data;
    int x;
    int y;
    EL* next;
    EL(int num, int i, int j) {
        data = num;
        x = i;
        y = j;
        next = NULL;
    }
};

struct Queue {
    EL* front;
    EL* back;
    int siz;
    Queue() {
        front = NULL;
        back = NULL;
        siz = 0;
    }

    void push(int num, int i, int j) {
        siz++;
        EL* t = new EL(num, i, j);
        if(front == NULL){
            back = t;
            front = t;
            return;
        }
        back->next = t;
        back = t;
    }

    EL* pop() {
        if (front == NULL) return NULL;
        siz--;
        EL* t = front;
        front = front->next;
        return t;
    }

    void printQueue(EL* t) {
        cout << t->data << " ";
        if (t->next != NULL) printQueue(t->next);
    }

};

Queue *q = new Queue();

void fillArr() {
    for (int i = 1; i <= m; i++) {
        int x, y, siz;
        cin >> x >> y >> siz;
        graph[x][y] = graph[y][x] = siz;
    }
}

void func(int k) {
    for (int i = 1; i <= n; i++) {
        if (graph[k][i] != 0 && isAdded[i] == 0) {
            q->push(graph[k][i], k, i);
        }
    }
}

void algPrima() {
    for (int i = 1; i <= n; i++) {
        if (isAdded[i] == 1) {
            func(i);
        }
    }
    //q->printQueue(q->front);
    //cout << "\n";
    //cout << q->siz << "\n";
    int min = pow(2.0, 30);
    int iMin = 0, jMin = 0;
    int temp = q->siz;
    for (int i = 1; i <= temp; i++) {
        EL *t = q->pop();
        if (t->data < min) {
            min = t->data;
            iMin = t->x;
            jMin = t->y;
        }
    }
    //cout << q->siz << "\n";
    graph2[iMin][jMin] = graph2[jMin][iMin] = min;
    isAdded[jMin] = isAdded[iMin] = 1;
}

void output() {
    int sum = 0;
    for (int i = 1; i <= n; i++) {
        for (int j = i + 1; j <= n; j++) {
            sum += graph2[i][j];
        }
    }
    cout << sum;
}

void printGraph() {
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= n; j++) {
            cout << graph2[i][j] << " ";
        }
        cout << "\n";
    }
}

int main() {
    cin >> n >> m;
    graph.assign(n + 1, vector <int>() );
    graph2.assign(n + 1, vector <int>() );
    way.assign(n + 1, 0);
    isAdded.assign(n + 1, 0);
    for (int i = 1; i <= n; i++) {
        graph[i].assign(n + 1, 0);
        graph2[i].assign(n + 1, 0);
    }
    fillArr();
    isAdded[1] = 1;
    for (int i = 2; i <= n; i++) {
        algPrima();
    }
    //printGraph();
    output();
}