from functools import reduce
n = (int)(input())
a = (list)(map(int, input().split()))


def gcd(a, b):
    # a>b
  while(b):
    c = a % b
    a = b
    b = c
  return a


def calcMod(a, m):
  return sum([m % v for v in a])


def lcm(a, b):
  return a*b/gcd(a, b)


def lcm_list(l):
  g = reduce(lcm, l)
  return g


print("ans", calcMod(a, (int)(lcm_list(a)-1)))
