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: import sys
  
  sys.setrecursionlimit(1000000)
  # def input():
  #    return sys.stdin.readline()[:-1]
  
  """
  n=int(input())
  for i in range(n):
      a[i]=int(input())
      a[i],b[i]=map(int,input().split())
  a=[int(x) for x in input().split()]
  n,m=map(int,input.split())
  
  """
  
  test_data1 = """\
  A??C
  """
  
  test_data2 = """\
  ACACAC
  """
  
  test_data3 = """\
  7
  994 518 941 851 647 2 581
  """
  
  test_data4 = """\
  ?AC?AC
  """
  td_num = 3
  
  
  def GetTestData(index):
      if index == 1:
          return test_data1
      if index == 2:
          return test_data2
      if index == 3:
          return test_data3
      if index == 4:
          return test_data4
  
  
  if False:
      with open("../test.txt", mode="w") as f:
          f.write(GetTestData(td_num))
      with open("../test.txt") as f:
          # Start Input code ---------------------------------------
          n = int(f.readline())
          a = [int(x) for x in f.readline().split()]
          # End Input code ---------------------------------------
  else:
      # Start Input code ---------------------------------------
      n = int(input())
      a = [int(x) for x in input().split()]
      # End Input code ---------------------------------------
  # print(n,a,sum(a)-n)
  print(sum(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"}]