import java.util.Scanner;

public class Main {

public static void main(String[] args) {

Scanner sc = new Scanner(System.in);

String s = sc.next();

switch (s) {

case "A+": System.out.println("4.3"); break;

case "A0": System.out.println("4.0"); break;

case "A-": System.out.println("3.7"); break;

case "B+": System.out.println("3.3"); break;

case "B0": System.out.println("3.0"); break;

case "B-": System.out.println("2.7"); break;

case "C+": System.out.println("2.3"); break;

case "C0": System.out.println("2.0"); break;

case "C-": System.out.println("1.7"); break;

case "D+": System.out.println("1.3"); break;

case "D0": System.out.println("1.0"); break;

case "D-": System.out.println("0.7"); break;

case "F": System.out.println("0.0"); break;

}

}

}