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 Java8 (OpenJDK 1.8.0) (judge verdict: Runtime Error)

import java.util.*;
public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int fiveHundred = sc.nextInt();
    int oneHundred = sc.nextInt();
    int fifty = sc.nextInt();
    int totalYen = sc.nextInt();
    int[] coins = new int[51];
    int count = 0;
    for (int i = 0; i <= 50; i++) {
      coins[i] = i;
    }
    for (int j = 0; j <= fiveHundred; j++) {
      for (int k = 0; k <= oneHundred; k++) {
        for (int l = 0; l <= fifty; l++) {
          if (500 * j + 100 * k + 50 * l == totalYen) {
            count++;
          }
        }
      } 
    }
    System.out.println(count);
  }
}