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: Runtime Error)

#include <stdio.h>
#include <stdlib.h>
 
int main()
{
    int n,i,j,a[2][101],p=0,m=0,max,sum;
    scanf("%d",&n);
    for(i=0;i<2;i++)
    for(j=0;j<n;j++)
    {
        scanf("%d",&a[i][j]);
    }
    max=0;
    for(j=0;j<n;j++)
    {
        max=max+a[1][j];
    }
    max=max+a[0][0];
    while(p<n)
    {
        sum=0;
        for(j=0;j<=m;j++)
        {
            sum=sum+a[0][j];
        }
    for(j=m;j<n;j++)
    {
        sum=sum+a[1][j];
    }
    if(max<sum)
    {
        max=sum;
    }
        m++;
        p++;
 
    }
    printf("%d\n",max);
    return 0;
}