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.*;
import java.util.*;

class Main{
	public static void main(String[] args) throws IOException{
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		String[] str = br.readLine().split(" ");
		int n = Integer.parseInt(str[0]);
		int q = Integer.parseInt(str[1]);
		@SuppressWarnings("unchecked")
		ArrayList<Integer>[] S = new ArrayList[n];
		for(int i = 0; i < n; i++) S[i] = new ArrayList<Integer>();
		for(int i = 0; i < q; i++){
			str = br.readLine().split(" ");
			int op = Integer.parseInt(str[0]);
			if(op == 0){
				int t = Integer.parseInt(str[1]);
				int x = Integer.parseInt(str[2]);
				S[t].add(x);
			}else if(op == 1){
				int t = Integer.parseInt(str[1]);
				if(S[t].isEmpty()) continue;
				System.out.println(S[t].get(S[t].size() - 1));
			}else{
				int t = Integer.parseInt(str[1]);
				if(S[t].isEmpty()) continue;
				S[t].remove(S[t].size() - 1);
			}
		}
	}
}