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 Perl (v5.18.2) (judge verdict: Wrong Answer)

main();


sub main{
	my $A = <STDIN>;
	my $B = <STDIN>;
	my $C = <STDIN>;
	my $X = <STDIN>;

	my $total = 500*$A + 100*$B + 50*$C;
	
	if($total < $X){ print "0\n"; last; }

	my $cnt = 0;

	for(my $a=0; $a<=$A; $a++){
		for(my $b=0; $b<=$B; $b++){
			for($c=0; $c<=$C; $c++){
				$total = 500*$a + 100*$b + 50*$c;
				if($total == $X){ $cnt++;}
			}
		}
	}
	
	print "$cnt\n" ;
	1;
}