import java.util.Scanner;

public class Main {

    public static void main(String[] args) {

    Scanner scanner  = new Scanner(System.in);

    float lasttest = scanner.nextInt();

    float thistest = scanner.nextInt();

    float tigao = (thistest - lasttest) / lasttest * 100;

    System.out.printf("%.2f%%",tigao);

    }

}