#include <iostream>
#include <iomanip>
using namespace std;

int main() {
    
    double price;
    cin >> price;

    double cost = 0.0;

    // write your code here.......
    

    if (price >= 5000)
        cout << price * 0.6 << endl;
    else if (price >= 2000)
        cout << price * 0.7 << endl;
    else if (price >= 500)
        cout << price * 0.8 << endl;
    else if (price >= 100)
        cout << price * 0.9 << endl;

    return 0;
}