// Author: Adrian Kuegel
// Complexity: O(n)
import java.io.*;
import java.util.*;

public class food {
	public static void main(String [] args) throws Exception {
		Scanner sc = new Scanner(System.in);
		int n;
		int [] requests = new int[101];
		int [] ps = new int[101];
		while((n = sc.nextInt()) != 0) {
			int a = sc.nextInt();
			int b = sc.nextInt();
			int total = 0;
			for (int i=1; i<=100; ++i)
				requests[i] = 0;
			for (int i=0; i<n; ++i) {
				int rsize = sc.nextInt();
				total += rsize;
				++requests[rsize];
			}
			int max_size = 100;
			while(requests[max_size] == 0)
				--max_size;
			ps[0] = 0;
			for (int i=1; i<=max_size; ++i)
				ps[i] = ps[i-1] + requests[i];
			int best = Integer.MAX_VALUE;
			for (int d=1; d<=3; ++d) {
				for (int i=max_size; i * 3 >= max_size * d; --i) {
					// biggest requested portion size which can be served as one portion
					int p1 = i / d;
					// biggest requested portion size which can be served as two portions
					int p2 = Math.min(i * 2 / d, max_size);
					// number of portions served is n * 3 - (number of people with at most 2 portions) - (number of people with at most 1 portion)
					int portion_cnt = n * 3 - ps[p2] - ps[p1];
					best = Math.min(best, a * (portion_cnt * i * 6 / d - total * 6) + b * portion_cnt * 6);
				}
			}
			if (best % 6 == 0)
				System.out.println(best / 6);
			else if (best % 2 == 0)
				System.out.println(best / 2 + " / 3");
			else if (best % 3 == 0)
				System.out.println(best / 3 + " / 2");
			else
				System.err.println("Something wrong here!");
		}
	}
}
