import array
import collections
import heapq

AdjacentVertex = collections.namedtuple("AdjacentVertex", "vertex cost")
INF = 2 ** 31 - 1
NO_VERTEX = -1
 
# Prim?????§??????0?????????????°???¨?????¨????±???????
def compute_mst_prim(max_v, adj_list):
    # pred[u]?????????u???????????¨???????????????????????¨???
    pred = collections.defaultdict(lambda: NO_VERTEX)
    # u??¨pred[u]????????¶???????????????key[u]?????\???
    key = collections.defaultdict(lambda: INF)
    key[0] = 0
    # ??????????????????????????????????????\?????¨????????¨??????
    pq = [(key[v], v) for v in range(max_v)]
    heapq.heapify(pq)
    # ????????????????????\?????????????????\??£???????????????????????????
    in_pq = array.array("B", (True for _ in range(max_v)))
    while pq:
        _, u = heapq.heappop(pq)
        in_pq[u] = False
        for v, v_cost in adj_list[u]:
            if in_pq[v]:
                weight = v_cost
                if weight < key[v]:
                    pred[v] = u
                    key[v] = weight
                    heapq.heappush(pq, (weight, v))
                    in_pq[v] = True
    return (pred, key)

max_v, max_e = map(int, input().split())
adjacency_list = collections.defaultdict(set)
for _ in range(max_e):
    s, t, w = map(int, input().split())
    adjacency_list[s].add(AdjacentVertex(t, w))
    adjacency_list[t].add(AdjacentVertex(s, w))
(_, key) = compute_mst_prim(max_v, adjacency_list)

print(sum(key.values()))import array
import collections
import heapq

AdjacentVertex = collections.namedtuple("AdjacentVertex", "vertex cost")
INF = 2 ** 31 - 1
NO_VERTEX = -1
 
# Prim?????§??????0?????????????°???¨?????¨????±???????
def compute_mst_prim(max_v, adj_list):
    # pred[u]?????????u???????????¨???????????????????????¨???
    pred = collections.defaultdict(lambda: NO_VERTEX)
    # u??¨pred[u]????????¶???????????????key[u]?????\???
    key = collections.defaultdict(lambda: INF)
    key[0] = 0
    # ??????????????????????????????????????\?????¨????????¨??????
    pq = [(key[v], v) for v in range(max_v)]
    heapq.heapify(pq)
    # ????????????????????\?????????????????\??£???????????????????????????
    in_pq = array.array("B", (True for _ in range(max_v)))
    while pq:
        _, u = heapq.heappop(pq)
        in_pq[u] = False
        for v, v_cost in adj_list[u]:
            if in_pq[v]:
                weight = v_cost
                if weight < key[v]:
                    pred[v] = u
                    key[v] = weight
                    heapq.heappush(pq, (weight, v))
                    in_pq[v] = True
    return (pred, key)

max_v, max_e = map(int, input().split())
adjacency_list = collections.defaultdict(set)
for _ in range(max_e):
    s, t, w = map(int, input().split())
    adjacency_list[s].add(AdjacentVertex(t, w))
    adjacency_list[t].add(AdjacentVertex(s, w))
(_, key) = compute_mst_prim(max_v, adjacency_list)

print(sum(key.values()))

### FIXED CODE ###

import heapq
from collections import defaultdict

INF = float('inf')


V, E = map(int, input().split())
Adj_list = defaultdict(set)

for i in range(E):
    s, t, w = map(int, input().split())
    Adj_list[s].add((t, w))
    Adj_list[t].add((s, w))
    
def prim(x):
    d = [INF] * x
    d[0] = 0
    isVisited = [False] * x
    hq = [(0,0)] 
    
    while hq:
        u = heapq.heappop(hq)[1]
        isVisited[u] = True
        
        for v, c in Adj_list[u]:
            if not isVisited[v] and d[v] > c:
                d[v] = c
                heapq.heappush(hq, (c, v))
    return sum(d)

print(prim(V))