#nullable enable using System.Numerics; void Run() { var n = Int(); var pz = n.Repeat(() => -1); var nz = n.Repeat(() => -1); var l2 = -1; var fz = new List(); for (var i = 0; i < n; i++) { var a = Int(); var b = Int(); if (a == 1) { nz[i + 1] = i; pz[i] = i + 1; } if (b == 1) { nz[i] = l2; pz[l2] = i; } if (b == 2) l2 = i; if (a < 1 && b < 2) fz.Add(i); } var ans = new List(); foreach (var fj in fz) { var j = fj; while (pz[j] >= 0) j = pz[j]; while (nz[j] >= 0) { ans.Add(j + 1); j = nz[j]; } ans.Add(j + 1); } Out(ans); } #region AtCoderIO _io_; var _backend_ = new StandardIOBackend(); _io_ = new(){ Backend = _backend_ }; Run(); _backend_.Flush(); string String() => _io_.Next(); int Int() => int.Parse(String()); void Out(object? x, string? sep = null) => _io_.Out(x, sep); class AtCoderIO { public required StandardIOBackend Backend { get; init; } Memory _input = Array.Empty(); int _iter = 0; public string Next() { while (_iter >= _input.Length) (_input, _iter) = (Backend.ReadLine().Split(' '), 0); return _input.Span[_iter++]; } public void Out(object? x, string? separator = null) { if (x == null) return; separator ??= Environment.NewLine; if (x is System.Collections.IEnumerable a and not string) { var objects = a.Cast(); if (separator == Environment.NewLine && !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(this int time, Func F) => Enumerable.Range(0, time).Select(_ => F()).ToArray(); }