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<vector>
#include<stack>
using namespace std;
int n,q;
int main()
{
	cin>>n>>q;
	vector<stack<int> >s(n);
	for(int i=0;i<q;i++)
	{
		int c;cin>>c;
		if(c==0)
		{
			int t,x;cin>>t>>x;
			s[t].push(x);
		}
		else if(c==1)
		{
			int p;cin>>p;
			if(!s[p].empty())cout<<s[p].top()<<endl;
		}
		else
		{
			int t;cin>>t;
			if(!s[t].empty())s[t].pop();
		}
	}
}