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 dist = new List<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) dist.Add(abs);
            }
        }
        dist = dist.Distinct().ToList();
        Console.WriteLine(dist.Count(x => x == dist.Min()) >= 2 ? 0 : dist.Min());
    }
}