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.