using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Text;
using System.Text.RegularExpressions;
using System.Linq;

class Magatro
{
    static void Main()
    {
        int N = int.Parse(Console.ReadLine());
        long[] Z = Console.ReadLine().Split(' ').Select(long.Parse).ToArray();
        Console.WriteLine("{0}/{1}", Z[N - 1], Z[0]);
    }

}