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 <algorithm>
#include <string>
#include <sstream>
#include <stack>

#define INPUT_FROM_FILE (0) 
#if INPUT_FROM_FILE
#include <fstream>
#endif

int main(int argc, char **argv){
	int n , q;
	std::string buf;
	std::vector<std::stack<long> > stacks;

#if INPUT_FROM_FILE
	std::ifstream ifs("test.txt");
	//FILE *fp = fopen("test.txt", "r");
#endif


#if INPUT_FROM_FILE
	std::getline(ifs, buf);
#else
	std::getline(std::cin, buf);
#endif
	{
		std::istringstream stream(buf);

		stream >> n >> q;
	}

	stacks.resize(n);
	for(int i = 0; i < q; i++){
#if INPUT_FROM_FILE
		std::getline(ifs, buf);
#else
		std::getline(std::cin, buf);
#endif
		std::istringstream stream(buf);
		long tmp, t, x;

		if(buf[0] == '0'){
			stream >> tmp >> t >> x;

			stacks[t].push(x);
		}
		else if(buf[0] == '1'){
			stream >> tmp >> t;

			if(!stacks[t].empty()){
				std::cout << stacks[t].top() << std::endl;
			}
		}
		else{
			stream >> tmp >> t;
			if(!stacks[t].empty()){
				stacks[t].pop();
			}
		}

	}

	return 0;
}