Problem:
Score : 100 points

Problem Statement

You went shopping to buy cakes and donuts with X yen (the currency of Japan).

First, you bought one cake for A yen at a cake shop.
Then, you bought as many donuts as possible for B yen each, at a donut shop.

How much do you have left after shopping?

Constraints

1 \leq A, B \leq 1 000

A + B \leq X \leq 10 000

X, A and B are integers.

Input

Input is given from Standard Input in the following format:

X
A
B

Output

Print the amount you have left after shopping.

Sample Input 1

1234
150
100

Sample Output 1

84

You have 1234 - 150 = 1084 yen left after buying a cake.
With this amount, you can buy 10 donuts, after which you have 84 yen left.

Sample Input 2

1000
108
108

Sample Output 2

28

Sample Input 3

579
123
456

Sample Output 3

0

Sample Input 4

7477
549
593

Sample Output 4

405

Solution in JavaScript (Node.js 12.16.1) (judge verdict: Wrong Answer)

function main(input) {
    const args = input.split('\n');
    const A = parseInt(args[0], 10),
          B = parseInt(args[1], 10),
          C = parseInt(args[2], 10),
          X = parseInt(args[3], 10);

    var count = 0;

    for (var a = 0; a <= A; ++a) {
        for (var b = 0; b <= B; ++b) {
            for (var c = 0; c <= C; ++c) {
                var sum = (a * 500) + (b * 100) + (c * 50);
                if (sum === X) ++count;
            }
        }
    }
    console.log(count);
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));