Implement a Stack using Linked List .

Input Format:
The first line of the input contains an integer 'T' denoting the number of test cases. Then T test cases follow.
First line of each test case contains an integer Q denoting the number of queries . 
A Query Q is of 2 Types
(i) 1 x   (a query of this type means  pushing 'x' into the stack)
(ii) 2     (a query of this type means to pop element from stack and print the poped element)
The second line of each test case contains Q queries seperated by space.

Output Format:
The output for each test case will  be space separated integers having -1 if the stack is empty else the element poped out from the stack . 
You are required to complete the two methods push which take one argument an integer 'x' to be pushed into the stack  and pop which returns a integer poped out from the stack.

Your Task:
Since this is a function problem, you don't need to take any input. Just complete the provided function.

Constraints:
1 <= T <= 100
1 <= Q <= 100
1 <= x <= 100

Example:
Input

2
5
1 2 1 3 2 1 4 2
4
2 1 4 1 5 2
Output
3 4
-1 5

Explanation:
In the first test case for query 
1 2    the stack will be {2}
1 3    the stack will be {2 3}
2       poped element will be 3 the stack will be {2}
1 4    the stack will be {2 4}
2       poped element will be 4

** For More Input/Output Examples Use 'Expected Output' option **

Contributor: Amit Khandelwal
Author: Shubham Joshi 1


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