from collections import defaultdict 


class Graph:
      
      def __init__(self, vertices):
            self. parent = defaultdict(int)
            self. rank = defaultdict(int) 
            self. V = vertices 
            self. graph = [] #we will append (u, v, w)
            
            
      def addEdge(self, u, v, w):
            self. graph. append([u, v, w])
      
      
      def find(self, v):
            if self. parent[v] == 0 :
                  return v 
            
            temp = self. find(self. parent[v])
            self. parent[v] = temp 
            
            return temp 
            
      def union(self, x, y):
            x_set = self. find(x) 
            y_set = self. find(y) 
            
            
            if self. rank[x_set] == self. rank[y_set]:
                  self. parent[x_set] = y_set 
                  self. rank[y_set] += 1  
            
            elif self. rank[x_set] < self. rank[y_set]: 
                  
                  self. parent[x_set] = y_set 
            
            else:
                  self. parent[y_set] = x_set 
                  
      def kruskal_Algo(self):
            self. graph = sorted(self. graph, key = lambda x: x[2] )
                        
            edges = 0 
            answer  = 0 
            for i in self. graph:
                  if edges == self. V - 1: 
                        break 
                  
                  u, v, w = i 
                  x = self. find(u)
                  y = self. find(v) 
                  
                  if x != y: 
                        edges += 1 
                        self. union(x, y)
                        answer += w 
                  
            print(answer)
            
def main():
      v, e = map(int, input(). split() )
      g = Graph(v)

      for i in range(e):
        u, v, w = map(int, input(). split() )
        g.addEdge(u, v, w)

      g. kruskal_Algo() 


if __name__ == '__main__':
      main()