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::stdin;

fn read_line() -> Vec<String> {
    let mut line = String::new();
    stdin().read_line(&mut line).expect("Failed to read line");
    return line.trim().split_whitespace().map(|s| s.to_string()).collect();
}

struct Reader {
    v: Vec<String>,
    n: usize,
}

impl Reader {
    fn new() -> Reader {
        let v = read_line();
        return Reader { v: v, n: 0 };
    }
    fn next<T>(&mut self) -> T where T: std::str::FromStr, T::Err: std::fmt::Debug {
        if self.n == self.v.len() {
            self.v = read_line();
            self.n = 0;
        }
        let x = self.v[self.n].parse().unwrap();
        self.n += 1;
        return x;
    }
    fn nexts<T>(&mut self, n: usize) -> Vec<T>
    where T: std::str::FromStr, T::Err: std::fmt::Debug {
        let mut v = Vec::with_capacity(n);
        for _ in 0..n {
            v.push(self.next());
        }
        return v;
    }
}

fn main() {
    let mut r = Reader::new();
    let n: usize = r.next();
    let a: Vec<u32> = r.nexts(n);
    let ans: u32 = a.iter().map(|x| x-1).sum();
    println!("{}", ans);
}