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 v5.12) (judge verdict: Wrong Answer)

const Release = function () {
    const fs = require('fs');
    const stdin = function (text) {
        if (text) console.log(text);
        return fs.readFileSync('/dev/stdin', 'utf8');
    }
    return stdin;
};


const debug = false;

const stdin = debug ? Debug() : Release();
const input = stdin().split(' ').map(x => parseInt(x));

const X = parseInt(input[0]);
const A = parseInt(input[0]);
const B = parseInt(input[0]);

const c = (X - A) % B;
console.log(c);