Problem:
Score : 100 points

Problem Statement

Snuke has a favorite restaurant.

The price of any meal served at the restaurant is 800 yen (the currency of Japan), and each time a customer orders 15 meals, the restaurant pays 200 yen back to the customer.

So far, Snuke has ordered N meals at the restaurant.
Let the amount of money Snuke has paid to the restaurant be x yen, and let the amount of money the restaurant has paid back to Snuke be y yen.
Find x-y.

Constraints

1 ≤ N ≤ 100

Input

The input is given from Standard Input in the following format:

N

Output

Print the answer.

Sample Input 1

20

Sample Output 1

15800

So far, Snuke has paid 16000 yen, and the restaurant has paid back 200 yen. Thus, the answer is 15800.

Sample Input 2

60

Sample Output 2

47200

Snuke has paid 48000 yen for 60 meals, and the restaurant has paid back 800 yen.

Solution in C (GCC 5.4.1) (judge verdict: Wrong Answer)

#include<stdio.h>
int main()
{
	int s,c;
	int q,w;
	int e,r;
	scanf("%d",&s);
	scanf("%d",&c);
	q=s*2;
/*	if(c>q)
	{
		w=c-q;
		e=w/4;
		r=e+s;
		printf("%d",r);
	}*/
	if(c<=q)
	{
		if(0==c%2)
		{
			w=c/2;
			printf("%d",w);
		}
		if(0!=c%2)
		{
			c--;
			w=c/2;
			printf("%d",w);
		}
	}
}