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

class Program
{
    static void Main()
    {
        long StaPos = 1;
        long EndPos = 2000000000;

        while (true) {
            long MidPos = EndPos / 2;
            if (EndPos < 2000000000) {
                MidPos = (StaPos + EndPos) / 2;
            }
            Console.WriteLine(MidPos);

            long GetVal = long.Parse(Console.ReadLine());
            if (GetVal == 1) {
                break;
                //StaPos = MidPos;
            }
            else {
                StaPos = MidPos;
            }
        }
    }
}