Problem:
Score : 300 points

Problem 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.

Constraints

All values in input are integers.

2 \leq N \leq 3000

2 \leq a_i \leq 10^5

Input

Input is given from Standard Input in the following format:

N
a_1 a_2 ... a_N

Output

Print the maximum value of f.

Sample Input 1

3
3 4 6

Sample Output 1

10

f(11) = (11\ mod\ 3) + (11\ mod\ 4) + (11\ mod\ 6) = 10 is the maximum value of f.

Sample Input 2

5
7 46 11 20 11

Sample Output 2

90

Sample Input 3

7
994 518 941 851 647 2 581

Sample Output 3

4527

Solution in Ruby (2.3.3) (judge verdict: Time Limit Exceeded)

n = gets.chomp.to_i
a = gets.chomp.split(' ').map(&:to_i)

max_sum = 0
ans = 0
max_lcm = 0

max_lcm = a.inject{|lcm, n| lcm.lcm(n)}

(1..a.max*10000).each do |m|
  # puts
  # puts m
  sum = 0
  a.each do |i|
    # puts "#{m} #{i} #{m % i}"
    sum += m % i
  end
  # puts sum
  if sum > max_sum
    max_sum = sum
    ans = m
  end
end

puts max_sum
# puts ans