using System;
using System.Collections.Generic;
using System.Linq;

class Program
{
    static void Main(string[] args)
    {
        var input = Console.ReadLine().Split().Select(int.Parse).ToArray();
        var N = input[0];
        var S = input[1];
        var K = input[2];

        var R = 0;
        var min = K + 1;

        for (int i = 0; i < N; i++)
        {
            var A = int.Parse(Console.ReadLine());
            var diff = Math.Abs(A - S);
            if (diff <= K && diff < min)
            {
                min = diff;
                R = i + 1;
            }
        }
        if (R == 0) Console.WriteLine("Unlucky!");
        else Console.WriteLine(R);
    }
}