# UnionFind

n,m=map(int,input().split())

Group = [i for i in range(n+1)] # グループ分け
Nodes = [1]*(n+1) # 各グループのノードの数

def find(x):
    while Group[x] != x:
        x=Group[x]
    return x

def Union(x,y):
    if find(x) != find(y):
        if Nodes[find(x)] < Nodes[find(y)]:
            
            Nodes[find(y)] += Nodes[find(x)]
            Nodes[find(x)] = 0
            Group[find(x)] = find(y)
            
        else:
            Nodes[find(x)] += Nodes[find(y)]
            Nodes[find(y)] = 0
            Group[find(y)] = find(x)

X=[list(map(int,input().split())) for i in range(m)]
X.sort(key=lambda x:x[2])

ANS=0
for a,b,w in X:
    if find(a)!=find(b):
        x=Nodes[find(a)]
        y=Nodes[find(b)]

        ANS+=w*x*y
        Union(a,b)

print(ANS)