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: Wrong Answer)

def erastosthenes(n)
  array = (2..n).to_a
  threshold = Math.sqrt(n)
  count = 2
  while threshold > count
    array.reject!{|n| n != count and n % count == 0}
    count += 1
  end
  array
end

lines = $stdin.read
array = lines.split("\n")

def mod(m, arr)
  arr.map do |a|
    m % a
  end.inject(&:+)
end

N = array[0].to_i
A = array[1].split(" ").map(&:to_i).sort

ans = 0

for e in erastosthenes(10**5)
  f = mod(e, A)
  ans = [f,ans].max
end

#p ans
puts ans