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 (1.15.1) (judge verdict: Accepted)

use std::io;

fn read_line()  -> String {
    let mut buf = String::new();
    io::stdin().read_line(&mut buf).expect("Couldn't read standard input");
    buf.trim().to_owned()
}

fn main() {
    let _n: i32 = read_line().parse().unwrap();
    let a: Vec<i32> = read_line()
        .split_whitespace()
        .map(|n| n.parse().unwrap())
        .collect();

    let mut sum: i32 = 0;
    for n in a.iter() {
        sum = sum + n - 1;
    }
    println!("{}", sum);
}