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"

#define REP(i, n, N) for(ll i=(n); i<(N); i++)
#define RREP(i, n, N) for(ll i=(N-1); i>=(n); i--)
#define LREP(lst,itr) for(auto itr = lst.begin(); itr != lst.end(); ++itr)
#define CK(n, a, b) ((a)<=(n)&&(n)<(b))
#define ALL(v) (v).begin(),(v).end()
#define MCP(a, b) memcpy(b,a,sizeof(b))
#define P(s) cout<<(s)<<endl
#define P2(a, b) cout<<(a)<<" "<<(b)<<endl
#define P3(a, b, c) cout<<(a)<<" "<<(b)<<" "<<(c)<<endl
#define V2(T) vector<vector<T>>
typedef long long ll;
using namespace std;
const ll MOD = 1e9 + 7;
const ll INF = 1e18;

int main(){
    int N, gift;
    cin >> N;
    gift = N/15;
    P(N*800 - gift*200);
}