7

package main

import (
	"fmt"
	"github.com/skorobogatov/input"
)
const INF = 2147483647

func coprofilling_min( min_e []int)  {
	for i := 0; i < len(min_e); i++ {min_e[i] = INF}
}
func filling_way(g []Vertex)  {
	for i := 0; i < len(g); i++ {
		g[i].edges = make([]int, len(g))
		for j := 0; j < len(g); j++ {
			g[i].edges[j] = INF
		}
	}
}
func ya_ebal_mamy_rombi(a, b int) int {
	if a < b {
		return a
	}else{
		return b
	}
}
func filling_dick_in_romans_mom_ass(m int, g []Vertex)  {
	for i := 0; i < m; i++ {
		var indexA, indexB, dist int
		input.Scanf("%d %d %d", &indexA, &indexB, &dist)
		g[indexA].edges[indexB] = dist
		g[indexB].edges[indexA] = dist
	}
}

type Vertex struct {
	edges []int
	used bool
}
func main() {
	var n, m int
	input.Scanf("%d \n %d", &n, &m)
	graph := make([]Vertex,n)
	filling_way(graph)
	filling_dick_in_romans_mom_ass(m, graph)
	var min_e[]int
	min_e = make([]int, n)
	coprofilling_min(min_e)
	PRIM := func(g []Vertex, min_e []int) int {
		min_e[0] = 0
		res := 0
		for i := 0; i < len(g); i++ {
			min1 := INF
			var u int
			for j := 0; j < len(g); j++ {
				if !g[j].used && min_e[j] < min1 {
					min1 = min_e[j]
					u = j
				}
			}
			res += min1
			g[u].used = true
			for v := 0; v < len(g); v++ {
				min_e[v] = ya_ebal_mamy_rombi(min_e[v],g[u].edges[v])
			}
		}
		return res
	}

	fmt.Println(PRIM(graph,min_e))
}