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 CPP):

Solution:
#include<iostream>
#include <bits/stdc++.h>

using namespace std;


int main()
{  	
	int n,m;
	int a,b,c;
	cin>>n>>m;
	stack <int> s[n];
	for(int i=1;i<=m;i++)
	{cin>>c;
		if(c==0)
		{
			cin>>a>>b;
			s[a].push(b);	
		}
		else if(c==1)
				{cin>>a;
				 if (!s[a].empty() )cout<<s[a].top()<<endl;}
		else if(c==2)
				{cin>>a;
				 if (!s[a].empty() )s[a].pop();
				 //cout<<endl;
				 }		 
	}
   
	
	
	
	return 0;
}