using System.Collections.Generic;

class Solution {
    static void Main(String[] args) {
        (Stack<int> s1, Stack<int> s2) = (new(), new());
        var n = int.Parse(Console.ReadLine());
        for (var _ = 0; _ < n; _++)
        {
            var parameters = Console.ReadLine().Split();
            var operation = parameters[0];
            switch (operation)
            {
                case "1":
                    s2.Push(int.Parse(parameters[1]));
                    break;
                case "2":
                case "3":
                    if (s1.Count == 0)
                    {
                        while (s2.Count > 0)
                        {
                            s1.Push(s2.Pop());
                        }
                    }
                    if (operation == "3")
                    {
                        Console.WriteLine(s1.Peek());
                        break;
                    }
                    s1.Pop();
                    break;
                default:
                    break;
            }
        }
    }
}