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 PYTHON3):

Solution:
class TwoDimStack():
    def __init__(self, num_stack):
        self.stacks = [[] for i in range(0, num_stack, 1)]

    def push(self, t, x):
        self.stacks[t].append(x)
        return self

    def top(self, t):
        if len(self.stacks[t]) > 0:
            print(f'{self.stacks[t][len(self.stacks[t])-1]}')
        return self

    def pop(self, t):
        if len(self.stacks[t]) > 0:
            self.stacks[t].pop()
        return self


num_stack, num_queue = tuple(map(int, input().split(' ')))
stacks = TwoDimStack(num_stack)

for i in range(0, num_queue):
    queue = tuple(map(int, input().split(' ')))
    if queue[0] == 0:
        stacks.push(queue[1], queue[2])
    elif queue[0] == 1:
        stacks.top(queue[1])
    elif queue[0] == 2:
        stacks.pop(queue[1])