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 vi vector<int>
  #define all(v) v.begin(),v.end()
  #define ll long long int
  #define  IOS    ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
  #define D1(x) {cerr<<" [" <<#x<<": "<<x<<"]";cout << endl;}
  #define D2(x) {cerr<<" [" <<#x<<": ";for(auto it:x)cerr<<it<< " ";cerr<<"] ";cout << endl;}

  const ll MOD=1e9+7;

  void solve(){
     ll n;
     cin >> n;
     cout << 800LL*(n) - 200*(n/15);
  }


  int main(){
    IOS
       solve();
       cerr <<endl <<"[ Time : " << (float)clock() / CLOCKS_PER_SEC << " secs ]" << endl;
  }
// integer overflow
// remember to clear visited array
// take input as vector<string> while using grid
// don't assign after modifying