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

class Program
{
    static void Main(string[] args)
    {
        var n = int.Parse(Console.ReadLine());
        var list = Console.ReadLine().Split(' ').Select(x => int.Parse(x)).ToArray();
        var dMap = new SortedDictionary<int, int>();
        var abs = 0;
        for (int i=0; i < n; i++)
        {
            for (int j=i+1; j < n; j++)
            {
                abs = Math.Abs(list[j] - list[i]);
                if (abs == 0) continue;
                if  (dMap.ContainsKey(abs)) dMap[abs]++;
                else dMap.Add(abs, 1);
            }
        }  
        Console.WriteLine(dMap.Count() != 0 ? dMap.ElementAt(0).Key : 0);
    }
}