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 <cstdio>
using namespace std;

struct StackOfInt {
	int *value;
	int max;
	int count;
	StackOfInt() {
		clear();
	}
	void clear() {
		max = 100;
		count = 0;
		value = new int[max];
	}
	void push(int x) {
		if (count > 0.9 * max) {
			int *temp = value;
			value = new int[max * 2];
			for (int i = 0; i < count; i++) 
				value[i] = temp[i];
			max = max * 2;
			delete[] temp;
		}
		value[count] = x;
		count++;
	}
	int top() {
		return value[count - 1];
	}
	void pop() {
		if (max != 100 && count < 0.2 * max) {
			int *temp = value;
			value = new int[max / 2];
			for (int i = 0; i < count; i++)
				value[i] = temp[i];
			max = max / 2;
			delete[] temp;
		}
		count--;
	}
	bool empty() {
		return count == 0;
	}
};

struct ArrayOfStack {
	int n;
	StackOfInt *value;
	ArrayOfStack(int x) {
		n = x;
		value = new StackOfInt[x];
	}
	void push(int t, int x) {
		value[t].push(x);
	}
	int top(int t) {
		return value[t].top();
	}
	void pop(int t) {
		value[t].pop();
	}
	bool empty(int t) {
		return value[t].empty();
	}
};

int main(void) {
	int n, q, com, t, x;
	cin >> n >> q;
	ArrayOfStack ar(n);
	while (q--) {
		cin >> com >> t;
		if (com == 0) {
			cin >> x;
			ar.push(t, x);
		} else if (com == 1) {
			if (!ar.empty(t))
				cout << ar.top(t) << endl;
		} else {
			if (!ar.empty(t))
				ar.pop(t);
		}
	}
}