N,M = map(int,input().split())
A = sorted([list(map(int,input().split())) for _ in range(M)],key=lambda x:x[2])
T = [0]+[[i,1] for i in range(1,N+1)]
def find(x):
    if T[x][0]==x:
        return x
    return find(T[x][0])
def union(x,y):
    rx = find(x)
    ry = find(y)
    if rx==ry:
        return
    if T[rx][1]>=T[ry][1]:
        T[ry][0] = rx
        T[rx][1] += T[ry][1]
    elif T[rx][1]<T[ry][1]:
        T[rx][0] = ry
        T[ry][1] += T[rx][1]
ans = 0
for i in range(M):
    a,b,w = A[i]
    ra = find(a)
    rb = find(b)
    if ra==rb:continue
    ans += w*T[ra][1]*T[rb][1]
    union(ra,rb)
print(ans)