100870: [AtCoder]ABC087 A - Buying Sweets

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