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 Rust (1.42.0) (judge verdict: Wrong Answer)

use proconio::input;

fn gcv(a:usize, b:usize)->usize {
  if b == 0 {
    a
  } else {
    gcv(b, a %b)
  }
}

fn lcm(a:usize, b:usize)->usize {
  a * b / gcv(a, b)
}

fn main() {
  input! {
    n: usize,
    vals: [usize; n]
  }
  
  let mut val = 1;
  for v in vals.iter() {
    val = lcm(val, *v);
  }

  let mut result = 0;
  let v = val - 1;
  let mut total = 0;
  for i in 0..n {
    total += v % vals[i];
  }
  result = std::cmp::max(result, total);
  println!("{}", result);
}