import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
double money = scanner.nextDouble();
if(money >= 5000) {
System.out.printf("%.1f", money * 0.6);
} else if(money >= 2000) {
System.out.printf("%.1f", money * 0.7);
} else if(money >= 500) {
System.out.printf("%.1f", money * 0.8);
} else if(money >= 100) {
System.out.printf("%.1f", money * 0.9);
} else if(money >= 0) {
System.out.printf("%.1f", money);
}
}
}