from __future__ import print_function
import sys

N = int(sys.stdin.readline())
K = int(sys.stdin.readline())

D = {}; done = 0

for line in sys.stdin:
  C1, C2, P1, P2 = line.split(); C1, C2 = map(int, (C1, C2))
  if P1 == P2: done += 1
  D.setdefault(P1, set()).add(C1)
  D.setdefault(P2, set()).add(C2)

doubles = len([ k for k, v in D.iteritems() if len(v) == 2 ])
singles = len([ k for k, v in D.iteritems() if len(v) == 1 ])

left    = N - 2*doubles - singles
answer  = doubles - done

if singles == 0 and left == 2:
  answer += 1
elif singles == left:
  answer += left

print(answer)