#include <iostream>

#include <vector>

#include <climits>

using namespace std;

int main()

{

	// fast io

	ios::sync_with_stdio(false);

	cin.tie(nullptr);

	cout.tie(nullptr);

	int N, a, b, x;

	while (cin >> N, N)

	{

		// init

		vector<int> student;

		int maxn = 0;

		pair<int, int> minn = { INT_MAX, 1 };

		// store data

		cin >> a >> b;

		for (int i = 0; i < N; ++i)

		{

			cin >> x;

			student.emplace_back(x * 6);

			maxn = max(maxn, x * 6);

		}

		// run all posible of n

		for (int div = 1; div <= 3; ++div) for (auto& i : student)

		{

			int s1 = i / div;

			int x = 0, y = 0;

			if (s1 * 3 < maxn) continue;			

			for (auto& j : student)

			{

				int s2 = j;

				while (s1 - s2 < 0) s2 -= s1, ++y;

				x += (s1 - s2);

				++y;

			}

			minn = min(minn, { x * a + y * b * 6, div });

		}

		auto& [i, j] = minn;

		if (i % 6 == 0) cout << i / 6;

		else cout << i * j / 6 << " / " << j;

		cout << "\n";		

	}

	return 0;

}