output_description: Print the maximum value of f.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      N
      a_1 a_2 ... a_N
attempt: # def gcd(a, b):
  # 	while b:
  # 		a, b = b, a % b
  # 	return a
  
  # def lcm(a, b):
  # 	return a * b // gcd (a, b)
  
  # def f(m, input):
  #   r = 0
  #   for i in input:
  #     r += m % i
  #   return r
  
  N = map(int, input())
  a_n = list(map(int, input().split(" ")))
  # a_n = sorted(a_n)
  
  max = 0
  for x in a_n:
      max += x
  
  # result = []
  # for m in range(max):
  # out = f(m, a_n)
  # result.append(out)
  # re = sorted(result)
  # print(re[-1])
  # print(max) #994 518 941 851 647 2 581 -> 4534
  print(max - len(a_n))
  
problem_description: Statement
  
  You are given N positive integers a_1, a_2, ..., a_N.
  
  For a non-negative integer m, let f(m) = (m\ mod\ a_1) + (m\ mod\ a_2) + ... +
  (m\ mod\ a_N).
  
  Here, X\ mod\ Y denotes the remainder of the division of X by Y.
  
  Find the maximum value of f.
samples: [{"input": "3\n    3 4 6", "output": "10\n    \n\nf(11) = (11\\ mod\\ 3) + (11\\ mod\\ 4) + (11\\ mod\\ 6) = 10 is the maximum value\nof f.\n\n* * *"}, {"input": "5\n    7 46 11 20 11", "output": "90\n    \n\n* * *"}, {"input": "7\n    994 518 941 851 647 2 581", "output": "4527"}]