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 JavaScript (node.js v5.12) (judge verdict: Runtime Error)

function gcd(a, b) {
    if (a < b) {
        var tmp = b;
        b = a;
        a = tmp;
    }

    if (b === 0) return a;
    return gcd(b, a%b);
}

function lcm(a, b) {
    return a * b / gcd(a, b);
}

function Main(input) {
    var inputArr = input.split('\n');
    var N = parseInt(inputArr[0]);
    var a = inputArr[1].split(' ').map(function(num) { return parseInt(num) });

    var koubai = 0;
    for (var i = 0 ; i < a.length - 1 ; ++i) {
        if (koubai === 0) koubai = lcm(a[i], a[i+1]);
        else koubai = lcm(koubai, a[i+1]);
    }

    var sum = 0;
    for (var i = 0 ; i < a.length ; ++i) {
        sum += (koubai*2-1)%a[i];
    }
    console.log(sum);
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));