belong=list()
group=list()
def init(X):
  global belong
  global group
  belong=list(range(X))
  group=[[i] for i in range(X)]

def unite(x,y):
  if len(group[belong[x]])<len(group[belong[y]]):
    x,y=y,x
  if belong[x]==belong[y]:
    return 0
  z=belong[y]
  V=len(group[z])*len(group[belong[x]])
  for i in range(len(group[z])):
    belong[group[z][-1]]=belong[x]
    group[belong[x]].append(group[z][-1])
    del group[z][-1]
  return V

N,M=map(int,input().split())
init(N)
X=[tuple(map(int,input().split())) for i in range(M)]
X.sort(key=lambda x:x[2])
ANS=0
for i in range(M):
  ANS+=X[i][2]*unite(X[i][0]-1,X[i][1]-1)
print(ANS)