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<bits/stdc++.h>
typedef long long int ll;
typedef unsigned long long int ull;
#define BIG_NUM 2000000000
#define MOD 1000000007
#define EPS 0.000000001
using namespace std;


#define NUM 1000

int N,num_query;
stack<int> S[NUM];

int main(){

	scanf("%d %d",&N,&num_query);

	int command,A,B;

	for(int loop = 0; loop < num_query; loop++){

		scanf("%d",&command);

		switch(command){
		case 0:

			scanf("%d %d",&A,&B);
			S[A].push(B);
			break;

		case 1:

			scanf("%d",&A);
			if(!S[A].empty()){
				printf("%d\n",S[A].top());
			}

			break;

		case 2:

			scanf("%d",&A);
			if(!S[A].empty()){
				S[A].pop();
			}
			break;
		}
	}

	return 0;
}