import java.util.*;
 
class Glowna {
	public static void main(String[] args){
		char a = ' ';
		int b = 0;
		Vector<Integer> stos = new Vector<Integer>();
		Scanner reader = new Scanner(System.in);
		while(reader.hasNext())
		{
			a = reader.next().charAt(0);
			if(a == '+' ){
				if(reader.hasNextInt()) b = reader.nextInt();
				if(stos.size()<10)
				{
					stos.addElement(b);
					System.out.println(":)");
				}
				else System.out.println(":(");
			}
			else if(a == '-' && stos.size() > 0)
			{
				System.out.println(stos.lastElement());
				stos.remove(stos.size()-1);
			}
			else System.out.println(":(");
		}
	}
}
 

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