using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
 
class Program
{
    static void Main(string[] args)
    {
        List<int> list = new List<int>();
        for (; ; )
        {
            char sign = char.Parse(Console.ReadLine());
 
            switch (sign)
            {
                case '+':
                    {
                        if (list.Count >= 10) Console.WriteLine(":(");
                        else
                        {
                            int number = int.Parse(Console.ReadLine());
                            list.Add(number);
                        }
                        break;
                    }
                case '-':
                    {
                        if (list.Count == 0) Console.WriteLine(":(");
                        else
                        {
                            Console.WriteLine(list[list.Count - 1]);
                            list.Remove(list[list.Count - 1]);
                        }
                        break;
                    }
 
            }
 
        }
 
 
    }
}
 

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+
1
+
2
+
3
+
4
+
5
+
6
+
7
+
8
+
9
+
0
+
1
-
-
-
-
-
-
-
-
-
-
-