"""

"""

import sys
from sys import stdin

class DSU():

    def __init__(self, n:int):

        self.n = n
        self.p = [i for i in range(n)]
        self.rank = [i for i in range(n)]
        self.sizelis = [1] * n

    def leader(self,a):
        stk = []
        while self.p[a] != a:
            stk.append(a)
            a = self.p[a]
        for v in stk:
            self.p[v] = a
        return a

    def merge(self, a, b):
        ap = self.leader(a)
        bp = self.leader(b)
        if ap == bp:
            return ap

        if self.rank[ap] > self.rank[bp]:
            self.p[bp] = ap
            self.sizelis[ap] += self.sizelis[bp]
        elif self.rank[ap] < self.rank[bp]:
            self.p[ap] = bp
            self.sizelis[bp] += self.sizelis[ap]
        else:
            self.p[bp] = ap
            self.sizelis[ap] += self.sizelis[bp]
            self.rank[ap] += 1
        return self.p[ap]

    def same(self,a,b):
        return self.leader(a) == self.leader(b)

    def size(self,a):
        return self.sizelis[ self.leader(a) ]

    def groups(self):
        dic = {}
        for v in range(self.n):
            vp = self.leader(v)
            if vp not in dic:
                dic[vp] = [v]
            else:
                dic[vp].append(v)
        return list(dic.values())


N,M = map(int,stdin.readline().split())

uf = DSU(N)

cab = []

for i in range(M):
    a,b,c = map(int,stdin.readline().split())
    cab.append( (c,a-1,b-1) )

cab.sort()
cab.reverse()

ans = 0
for c,a,b in cab:

    if not uf.same(a,b):
        uf.merge(a,b)
        ans += c*2

print (ans)