# -*- coding: utf-8 -*-

import functools
import fractions 

N = int(input())
numbers = list(map(int, input().split()))

max_under_lcm = functools.reduce(lambda x, y: int((x * y) / fractions.gcd(x,y)), numbers) - 1
answer = sum([max_under_lcm % n for n in numbers])

print(answer)