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.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main{

	public static void main(String[] args) {

				Scanner sc = new Scanner(System.in);
				int n = sc.nextInt();
				List<List<Integer>> A = new ArrayList<>();
				for (int i = 0; i <= n; i++) {
					List<Integer> a = new ArrayList<>();
					A.add(a);
				}
				int z = sc.nextInt();
				for (int i = 0; i < z; i++) {
					int q = sc.nextInt();
					if (q == 0) {
						int x = sc.nextInt();
						int t = sc.nextInt();
						List<Integer> a = A.get(x);
						a.add(t);
					}
					if (q == 1) {
						int x = sc.nextInt();
						if (A.get(x).size()!= 0) {
							System.out.println(A.get(x).get(A.get(x).size()-1));
						}
					}
					if (q == 2) {
						int x = sc.nextInt();
						if (A.get(x).size()!= 0) {
						A.get(x).remove(A.get(x).size()-1);
						}
					}
				}
				sc.close();
			}
}