using System;
using System.Linq;

public class Program
{
    static void Main()
    {
        string s = Console.ReadLine();
        int N = int.Parse(s);

        s = Console.ReadLine();
        var t = s.Split(' ');
        var D = new int[N];
        for (int i = 0; i < N; ++i) {
            D[i] = int.Parse(t[i]);
        }
        Array.Sort(D);

        s = Console.ReadLine();
        t = s.Split(' ');

        int x = int.Parse(t[0]);
        int y = int.Parse(t[1]);

        int X = Math.Abs(x + y);
        int Y = Math.Abs(x - y);

        if (D.Contains(Math.Max(X, Y))) {
            Console.WriteLine(1);
        } else if (N >= 2 && D[N-1] + D[N-2] >= Math.Max(X, Y)) {
            Console.WriteLine(2);
        } else {
            Console.WriteLine(-1);
        }
    }
}