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.util.*;

public class Main {
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int m = sc.nextInt();
		ArrayList<ArrayDeque<Integer>> lists = new ArrayList<>();
		for (int i = 0; i < n; i++) {
		    lists.add(new ArrayDeque<>());
		}
		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < m; i++) {
		    int type = sc.nextInt();
		    if (type == 0) {
		        lists.get(sc.nextInt()).push(sc.nextInt());
		    } else if (type == 1) {
		        int idx = sc.nextInt();
		        if (lists.get(idx).size() > 0) {
		            sb.append(lists.get(idx).peek()).append("\n");
		        }
		    } else {
		        int idx = sc.nextInt();
		        if (lists.get(idx).size() > 0) {
		            lists.get(idx).pop();
		        }
		    }
		}
		System.out.print(sb);
	}
}