blabla

using System;
using System.Collections.Generic;
using System.Numerics;

namespace Masha
{
    internal class Program
    {
        private static BigInteger GCD(BigInteger a, BigInteger b)
        {
            while (a != 0 && b != 0)
            {
                if (a > b)
                    a %= b;
                else
                    b %= a;
            }

            return a | b;
        }

        private static BigInteger abs(BigInteger a)
        {
            if (a < 0)
            {
                return a * -1;
            }
            return a;
        }
        public static void Main(string[] args)
        {
            BigInteger n = 3977;
            BigInteger x = 2;
            BigInteger y = 1;

            BigInteger step = 1;
            for (int i = 1; i < n; i++)
            {
                BigInteger x_prev = x;
                if (GCD(n, abs(x_prev-y)) != 1)
                {
                    break;
                }

                x = (x * x - 1) % n;

                if (i == step)
                {
                    step *= 2;
                    y = x_prev;
                }
                Console.WriteLine(GCD(n,abs(x-y)));
            }
        }

    }
}