using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static int[][] NArr(long n) => Enumerable.Repeat(0, (int)n).Select(_ => NList).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var c = NList;
        var (n, m, a, b) = (c[0], c[1], c[2], c[3]);
        c = NList;
        var plist = PList(n);
        var INF = long.MaxValue / 2;
        var len = Enumerable.Repeat(INF, plist.Count).ToArray();
        len[0] = 0;
        for (var i = 0; i < plist.Count; ++i)
        {
            var minci = int.MaxValue;
            foreach (var ci in c) if (ci % plist[i] == 0)
            {
                minci = ci;
                break;
            }
            for (var j = i + 1; j < plist.Count; ++j)
            {
                if (minci <= plist[j]) break;
                if (plist[j] % plist[i] == 0)
                {
                    if (j + 1 == plist.Count) len[j] = Math.Min(len[j], len[i] + (long)(plist[j] / plist[i] - 1) * a);
                    else len[j] = Math.Min(len[j], len[i] + (long)(plist[j] / plist[i] - 1) * a + b);
                }
            }
        }
        WriteLine(len.Last() == INF ? -1 : len.Last());
    }
    static List<int> PList(int n)
    {
        var ans = new List<int>();
        var rev = new List<int>();
        for (var i = 1; i * i <= n; ++i)
        {
            if (n % i == 0)
            {
                ans.Add(i);
                if (i * i < n) rev.Add(n / i);
            }
        }
        rev.Reverse();
        return ans.Concat(rev).ToList();
    }
}