#t = int(input())
t = 1
for _ in range(t):
  n,m,k = map(int, input().split())
  cou = [0]*n
  tf = [False]*n
  for i in range(m):
    a,b = map(int, input().split())
    a -= 1
    b -= 1
    cou[b] += 1
    tf[a] = True
  lis = []
  aa = tf.count(True)
  res = (k+1)-aa
  for i in range(n):
    if not tf[i]:
      lis.append(cou[i])
  lis.sort(reverse = True)
  ans = 0
  for i in range(n):
    if tf[i]:
      ans += min(cou[i],k)
  for i in range(res):
    ans += min(k,lis[i])
  print(max(aa,k+1)*k - ans)