# UnionFind 参考は以下のサイト
# https://note.nkmk.me/python-union-find/
from collections import defaultdict
import heapq

class UnionFind():
    def __init__(self, n):
        self.n = n
        self.parents = [-1] * n

    def find(self, x):
        if self.parents[x] < 0:
            return x
        else:
            self.parents[x] = self.find(self.parents[x])
            return self.parents[x]

    def union(self, x, y):
        x = self.find(x)
        y = self.find(y)

        if x == y:
            return

        if self.parents[x] > self.parents[y]:
            x, y = y, x

        self.parents[x] += self.parents[y]
        self.parents[y] = x

    def size(self, x):
        return -self.parents[self.find(x)]

    def same(self, x, y):
        return self.find(x) == self.find(y)

    def members(self, x):
        root = self.find(x)
        return [i for i in range(self.n) if self.find(i) == root]

    def roots(self):
        return [i for i, x in enumerate(self.parents) if x < 0]

    def group_count(self):
        return len(self.roots())

    def all_group_members(self):
        group_members = defaultdict(list)
        for member in range(self.n):
            group_members[self.find(member)].append(member)
        return group_members

    def __str__(self):
        return '\n'.join(f'{r}: {m}' for r, m in self.all_group_members().items())


N,M = map(int, input().split())
ABW = [list(map(int, input().split())) for _ in range(M)]
H = []
for a,b,w in ABW:
    heapq.heappush(H,(w,a,b))
uf = UnionFind(N)
ans = 0
while H:
    w,a,b = heapq.heappop(H)
    a-=1
    b-=1
    if not uf.same(a,b):
        ans += uf.size(a)*uf.size(b)*w
        uf.union(a,b)

print(ans)