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 C (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<stdio.h>
int main(void)
{
    int A,B,C,X,count=0;
    scanf("%d",&A);
    scanf("%d",&B);
    scanf("%d",&C);
    scanf("%d",&X);
    for(int i=0;i<=A;i++)
    {
        int Z = X;
        Z = Z - (500*i);
        for(int j=0;j<=B;j++)
        {
            Z = Z - (100*j);
            for(int k=0;k<=C;k++)
            {
                if(Z==50*k)
                {
                    count++;
                    //printf("%d %d %d %d\n",Z,i,j,k);
                }
            }
        }
    }
    printf("%d",count);
}