#nullable enable

using System.Numerics;

var _backend_ = new StandardIOBackend();

object? Solve()
{
    var max = 1000000000;
    for (var i = 0; i < 30; i++)
    {
        var x = max / 2 + 1;
        Out(x);
        _backend_.Flush();
        var response = Int();
        if (response > 0) break;
        max /= 2;
    }
    return null;
    // var ans = 0;
    // var n = Int();
    // var m = Int();
    // for (var i = 0; i < n; i++)
    // {
    //     var s = String();
    //     var r = Int();
    //     if (r < 1200) continue;
    //     var pass = true;
    //     for (var j = 0; j < 4; j++) if (s[j] == 'x') pass = false;
    //     if (!pass) ans++;
    // }
    // return ans;
}

#region
AtCoderIO _io_;
_io_ = new(){ Backend = _backend_ };
Out(Solve());
_backend_.Flush();

string String() => _io_.Next();
int Int() => int.Parse(String());
void Out(object? x, string? sep = null) => _io_.Out(x, sep ?? Environment.NewLine);

class AtCoderIO
{
    public required StandardIOBackend Backend { get; init; }

    Memory<string> _input = Array.Empty<string>();
    int _iter = 0;
    public string Next()
    {
        while (_iter >= _input.Length) (_input, _iter) = (Backend.ReadLine().Trim().Split(' '), 0);
        return _input.Span[_iter++];
    }

    public void Out(object? x, string separator)
    {
        if (x == null) return;
        if (x is System.Collections.IEnumerable a and not string)
        {
            var objects = a.Cast<object>();
            if (!objects.Any()) return;
            x = string.Join(separator, objects);
        }
        Backend.WriteLine(x);
    }
}

class StandardIOBackend
{
    readonly StreamReader _sr = new(Console.OpenStandardInput());
    readonly StreamWriter _sw = new(Console.OpenStandardOutput()) { AutoFlush = false };
    public string ReadLine() => _sr.ReadLine()!;
    public void WriteLine(object? value) => _sw.WriteLine(value);
    public void Flush() => _sw.Flush();
}
#endregion

static class Extensions
{
    public static T[] Repeat<T>(this int time, Func<T> F) => Enumerable.Range(0, time).Select(_ => F()).ToArray();
}