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 <stack>
#include <vector>
#include <iostream>

using namespace std;

int main() {
	int n,q;
	cin >> n >> q;
	vector< stack<int> > sv(n);
	while (q--) {
		int op,t;
		cin >> op >> t;
		switch (op) {
			case 0:		// push
				int x;
				cin >> x;
				sv[t].push(x);
				break;
			case 1:		// top
				if (!sv[t].empty()) {
					cout << sv[t].top() << endl;
				}
				break;
			default:	// pop
				if (!sv[t].empty()) {
					sv[t].pop();
				}
		}
	}	
}