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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include<bits/stdc++.h>
using namespace std;
#define ll        long long
#define  sci(x)   scanf("%d", &x)
#define  scl(x)   scanf("%lld", &x)
#define  scd(x)   scanf("%lf", &x)
#define l0(i,n)   for(ll i=0; i<n; i++)

int main ()
{
	ios::sync_with_stdio(0);
	cin.tie(0);
	//CODE TONOY
	int n;
	int sum=0;
	cin>>n;
	for(int i=1;i<=n;i++){
		if (i%15==0)
		sum+=600;
		
		else
		sum+=800;
	}
	cout<<sum;	
	return 0;
}