import sys
sys.setrecursionlimit(10 ** 8)


N,M = map(int,input().split())
edge = []
C = 20
mask = 1 << C
for _ in range(M):
    a,b,w = map(int,input().split())
    edge.append((w,(a << C) + b))
edge.sort()

ans = 0
parent = [-1] * N
def find(i):
    if parent[i] < 0:return i
    parent[i] = find(parent[i])
    return parent[i]
def unite(i,j):
    I = find(i)
    J = find(j)
    if I == J:return False
    if parent[I] < parent[J]:
        I,J = J,I
    parent[J] += parent[I]
    parent[I] = J
    return True
def isSame(i,j):
    return find(i) == find(j)
for w,k in edge:
    a = k // mask
    b = k % mask
    #print(w,a,b)
    a -= 1
    b -= 1
    A = find(a)
    B = find(b)
    if A == B:continue
    na = -parent[A]
    nb = -parent[B]
    ans += w * na * nb
    unite(a,b)
    #print(na,nb,w)
print(ans)