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<T: std::str::FromStr>(i: &mut StdinLock) -> T {
    let mut s = String::new();
    i.by_ref().read_line(&mut s).ok();
    s.trim().parse().ok().unwrap()
}

fn reads<T: std::str::FromStr>(i: &mut StdinLock) -> Vec<T> {
    let mut s = String::new();
    i.by_ref().read_line(&mut s).ok();
    s.trim()
        .split_whitespace()
        .map(|e| e.parse().ok().unwrap())
        .collect()
}

fn main() {
    // initialize stdin
    let sin = std::io::stdin();
    let mut sin = sin.lock();
    let sin = &mut sin;

    let _n: usize = read(sin);
    let ax: Vec<i64> = reads(sin);

    let ans: i64 = ax.into_iter().map(|x| x - 1).sum();

    println!("{}", ans);
}