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 Java8 (OpenJDK 1.8.0) (judge verdict: Wrong Answer)

import java.io.BufferedReader;
import java.io.InputStreamReader;
 
public class Main {
    public static void main(String[] args) throws Exception {
        
        int y = 0;
        int x = 0;
        
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        
        System.out.println("食べた回数を入力してください：");
        String line = br.readLine();
        
        
        int n = Integer.parseInt(line);
        
        for (int i = 0;i < n;i++){
            x = x + 800;
            
                if (i / 15 == 0){
                    y = y + 200;
            } 
        } 
        
		System.out.println("今までに支払った金額…　" + x + "円");
		System.out.println("今までにもらった金額…　" + y + "円");
	}
}