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 Java8 (OpenJDK 1.8.0) (judge verdict: Accepted)

/**
 * TODO: delete this line
 */


import java.math.BigInteger;
import java.util.Scanner;

/**
 * TODO: Rename to Main
 */
class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int N = scanner.nextInt();
        int[] as = new int[N];

        for (int i = 0; i < N; i++) {
            as[i] = scanner.nextInt();
        }

        BigInteger lcm = BigInteger.valueOf(1);
        for (int a : as) {
            lcm = lcm(lcm, BigInteger.valueOf(a));
        }

        BigInteger sum = BigInteger.valueOf(0);
        for (int a : as) {
            sum = sum.add((lcm.subtract(BigInteger.valueOf(1))).mod(BigInteger.valueOf(a)));
        }
        System.out.println(sum);
    }

    private static BigInteger lcm(BigInteger m, BigInteger n) {
        return m.multiply(n).divide(gcd(m, n));
    }

    private static BigInteger gcd(BigInteger m, BigInteger n) {
        return m.gcd(n);
    }
}