botanics

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

namespace Q10407
{
    class Program
    {
        static private int[] iarr; static private char[] par = { ' ' }; static private int temp; static private bool tof;
        static void Main(string[] args)
        {
            for (; ; )
            {
            label: Console.Write("Integer>>>");
                try
                {
                    iarr = Array.ConvertAll<string, int>(Console.ReadLine().Split(par, StringSplitOptions.RemoveEmptyEntries), int.Parse);
                }
                catch { goto label; }
                tof = true;
                for (int j = Math.Abs(iarr.Min()); j >= 1; j--)
                {
                    int t1 = iarr[0] % j; int t2 = iarr[1] % j;
                    if (t1 < 0) t1 += j; if (t2 < 0) t2 += j;
                    if (t1 == t2)
                    {
                        temp = t1;
                        for (int i = 2; i < iarr.Length; i++)
                        {
                            t2 = iarr[i] % j; t2 += t2 < 0 ? j : 0;
                            if (temp != t2) break;
                            if (i == iarr.Length - 1) { Console.WriteLine("Ans={0}", j); tof = false; }
                        }
                    }
                    if (!tof) break;
                }
            }
        }
    }
}