import java.math.BigDecimal;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		String D = scan.next();
		scan.close();
		BigDecimal big = new BigDecimal(D);
		BigDecimal r = new BigDecimal("1.08");

		BigDecimal ans = big.multiply(r);
		System.out.println(ans);

	}
}