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, re
  from collections import deque, defaultdict, Counter
  from math import (
      ceil,
      sqrt,
      hypot,
      factorial,
      pi,
      sin,
      cos,
      tan,
      asin,
      acos,
      atan,
      radians,
      degrees,
      log2,
  )
  from itertools import (
      accumulate,
      permutations,
      combinations,
      combinations_with_replacement,
      product,
      groupby,
  )
  from operator import itemgetter, mul
  from copy import deepcopy
  from string import ascii_lowercase, ascii_uppercase, digits
  from bisect import bisect, bisect_left
  from fractions import gcd
  from heapq import heappush, heappop
  from functools import reduce
  
  
  def input():
      return sys.stdin.readline().strip()
  
  
  def INT():
      return int(input())
  
  
  def MAP():
      return map(int, input().split())
  
  
  def LIST():
      return list(map(int, input().split()))
  
  
  def ZIP(n):
      return zip(*(MAP() for _ in range(n)))
  
  
  sys.setrecursionlimit(10**9)
  INF = float("inf")
  mod = 10**9 + 7
  
  N = INT()
  a = LIST()
  
  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"}]