Problem: Stack is a container of elements that are inserted and deleted according to LIFO (Last In First Out).

For $n$ stack $S_i$ ($i = 0, 1, ..., n-1$), perform a sequence of the following operations.

* push($t$, $x$): Insert an integer $x$ to $S_t$.
* top($t$): Report the value which should be deleted next from $S_t$. If $S_t$ is empty, do nothing.
* pop($t$): Delete an element from $S_t$. If $S_t$ is empty, do nothing.



In the initial state, all stacks are empty.

Constraints

* $1 \leq n \leq 1,000$
* $1 \leq q \leq 200,000$
* $-1,000,000,000 \leq x \leq 1,000,000,000$

Input

The input is given in the following format.


$n \; q$
$query_1$
$query_2$
:
$query_q$


Each query $query_i$ is given by


0 $t$ $x$


or


1 $t$


or


2 $t$


where the first digits 0, 1 and 2 represent push, top and pop operations respectively.

Output

For each top operation, print an integer in a line.

Example

Input

3 9
0 0 1
0 0 2
0 0 3
0 2 4
0 2 5
1 0
1 2
2 0
1 0


Output

3
5
2

Solution (in JAVA):

Solution:
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Stack;

public class Main{

	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String[] tmpArray = br.readLine().split(" ");
		int n = Integer.parseInt(tmpArray[0]);
		int q = Integer.parseInt(tmpArray[1]);

		@SuppressWarnings("unchecked")
		Stack<Integer>[] stackArray = new Stack[n];
		for(int i = 0; i < n; i++){
			stackArray[i] = new Stack<Integer>();
		}

		for(int i = 0; i < q; i++){
			tmpArray = br.readLine().split(" ");

			//push
			if(tmpArray[0].equals("0")){
				int t = Integer.parseInt(tmpArray[1]);
				int x = Integer.parseInt(tmpArray[2]);

				stackArray[t].push(x);
			}
			//top
			else if(tmpArray[0].equals("1")){
				int t = Integer.parseInt(tmpArray[1]);

				if(!stackArray[t].isEmpty()){
					System.out.println(stackArray[t].peek());
				}
			}
			//pop
			else {
				int t = Integer.parseInt(tmpArray[1]);

				if(!stackArray[t].isEmpty()){
					stackArray[t].pop();
				}
			}
		}

	}
}