output_description: Print x rounded up to the nearest integer.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      a b
attempt: def compare(a, A):
      R = 0
      for i in range(0, len(A)):
          if a == A[i]:
              R += 1
          elif a < A[i]:
              break
      return R
  
  
  def result(R, a):
      if R == a:
          return 0
      elif a < R:
          return R - a
      return R
  
  
  N = int(input())
  
  a = list(map(int, input().split()))
  a.sort()
  
  R = 0
  T = compare(a[0], a)
  R += result(T, a[0])
  
  for i in range(1, N):
      if a[i] != a[i - 1]:
          C = compare(a[i], a[T:])
          R += result(C, a[i])
          T += C
  
  print(R)
  
problem_description: Statement
  
  You are given two positive integers a and b. Let x be the average of a and b.
  Print x rounded up to the nearest integer.
samples: [{"input": "1 3", "output": "2\n    \n\nThe average of 1 and 3 is 2.0, and it will be rounded up to the nearest\ninteger, 2.\n\n* * *"}, {"input": "7 4", "output": "6\n    \n\nThe average of 7 and 4 is 5.5, and it will be rounded up to the nearest\ninteger, 6.\n\n* * *"}, {"input": "5 5", "output": "5"}]