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# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Text;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static void Main(string[] args) {
#if DEBUG
        System.Diagnostics.Debug.WriteLine("-----TextFile1");
        System.Diagnostics.Debug.WriteLine(process("../TextFile1.txt"));
        System.Diagnostics.Debug.WriteLine("-----TextFile2");
        System.Diagnostics.Debug.WriteLine(process("../TextFile2.txt"));
        System.Diagnostics.Debug.WriteLine("-----TextFile3");
        System.Diagnostics.Debug.WriteLine(process("../TextFile3.txt"));
#endif

#if !DEBUG
        String ret = process(new System.IO.StreamReader(Console.OpenStandardInput()));
        Console.WriteLine(ret);
#endif
    }

    static string process(string filePath) {
        using (var input = new System.IO.StreamReader(filePath)) {
            if(input.EndOfStream) return "NO PROC";
            return process(input);
        }
    }

    static string process(System.IO.TextReader input) {
        int n     = int.Parse(input.ReadLine());
        int r = 800 * n - 200 * (n / 15);
        return "" + r;
    }
    
}