/**
 * Suit Distribution Problem.
 * 
 * @author John Paxton
 * @version May 20, 2014
 */

import java.io.*;
import java.util.Scanner;

public class Suit
{
    public static void main (String [] args) throws FileNotFoundException
    {
        Scanner in = new Scanner (new File ("suit.in"));
        PrintWriter out = new PrintWriter (new File ("suit.out"));
        int hand_1 = in.nextInt();
        int hand_2 = in.nextInt();
        
        while ((hand_1 != -1) && (hand_2 != -1))
        {
            out.print(hand_1 + "-" + hand_2 + " split: ");
            out.format("%.8f\n", calculate(hand_1, hand_2));
            hand_1 = in.nextInt();
            hand_2 = in.nextInt();
        }
        
        out.close();
    }
    
    private static double calculate (int hand_1, int hand_2)
    {
        double answer;
        
        answer = combo(hand_1 + hand_2, hand_1) * 
                combo(26 - hand_1 - hand_2, 13 - hand_1) / 
                combo(26, 13);
                
        if (hand_1 != hand_2)
        {
            answer *= 2;
        }
                
        return answer;
    }
    
    private static double combo (int n, int k)
    {
        double answer = 1;
        
        for (int i = k + 1; i <= n; i++)
        {
            answer *= i;
        }
        
        for (int i = 2; i <= n - k; i++)
        {
            answer /= i;
        }
        
        return answer;
    }
}