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>

using namespace std;


int main() {
	int n,q;
	cin >> n >> q;

	int a, b,c;
	vector<stack<int>> aa(n,stack<int>());
	for (int i = 0; i <q; i++) {
		cin >> a >> b  ;
		if (a == 0) {
			cin >> c;
			aa[b].push(c);
		}
		if (a == 1) {
			if (!aa[b].empty()) {
				cout << aa[b].top() << endl;
			}
		}
		if (a == 2) {
			if (!aa[b].empty()) {
				aa[b].pop();
			}
		}
	}

}