#include <iomanip>
using namespace std;

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

    double cost = 0.0;

    // write your code here.......
    if(price<0)
        return -1;
    if(price>=5000){
         cost=price*0.6;
    }else if(price>=2000){
         cost=price*0.7;
    }else if(price>=500){
        cost= price*0.8;
    }
    else if(price>=100){
        cost=price*0.9;
    }else if(price>0 && price<100){
        cost=price ;
    }

    cout << setiosflags(ios::fixed) << setprecision(1) << cost << endl;

    return 0;
}