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?

Input

Input is given from Standard Input in the following format:
X
A
B

Output

Print the amount 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.

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

见题面 Input 部分

见题面 Output 部分