import java.util.*;

class JY_42861 {

static int[] parents;

public int solution(int n, int[][] costs) {

int answer = 0;

parents = new int[n];

for(int i=0; i<n; i++) {

parents[i] = i;

}

// 비용 순으로 정렬

Arrays.sort(costs, (o1, o2)->(o1[2]-o2[2]));

for(int[] cost: costs) {

if(find(cost[0]) != find(cost[1])) {

union(cost[0], cost[1]);

answer += cost[2];

}

}

return answer;

}

public static int find(int x) {

if(parents[x] != x) {

parents[x] = find(parents[x]);

}

return parents[x];

}

public static void union(int a, int b) {

int pa = find(a);

int pb = find(b);

if(pa != pb) {

parents[pb] = pa;

}

}

}