/*Jonathan Walker

Langham Creek High School

Senior 3 Contest #1*/

import java.util.*;

import java.io.*;

public class ACSL_probability

{

private static int total,red,blue,white,num;

private static boolean replace;

private static ArrayList<Character> marbles=new ArrayList();

private static int numerator,denominator;

public static void main(String[] args)throws IOException

{

Scanner file=new Scanner(new File("ascon106.txt"));

while(file.hasNextLine())

{

Scanner sc=new Scanner(file.nextLine()).useDelimiter(", ");

marbles.clear();

num=sc.nextInt();

if(num==0)

{

System.out.println("none.");

continue;

}

red=sc.nextInt();

blue=sc.nextInt();

white=sc.nextInt();

total=red+blue+white;

numerator=1;

denominator=1;

if(num>1) replace=(sc.next().charAt(0)=='Y' ? true : false);

for(int a=0;a<num;a++)

{

marbles.add(sc.next().charAt(0));

}

//System.out.println(num+" "+red+" "+blue+" "+white+" "+total+" "+replace+" "+marbles);

while(marbles.size()>0)

{

// System.out.print(marbles);

char c=marbles.remove(0);

switch(c)

{

case 'R':

numerator*=red;

denominator*=total;

if(!replace) red--;

break;

case 'B':

numerator*=blue;

denominator*=total;

if(!replace) blue--;

break;

case 'W':

numerator*=white;

denominator*=total;

if(!replace) white--;

break;

case 'r':

numerator*=(total-red);

denominator*=total;

break;

case 'b':

numerator*=(total-blue);

denominator*=total;

break;

case 'w':

numerator*=(total-white);

denominator*=total;

break;

}

if(!replace) total--;

}

System.out.println(numerator+"/"+denominator);

}

}

}