Time Limit : sec, Memory Limit : KB

# Stack

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.

## 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.

## Constraints

• $1 \leq n \leq 1,000$
• $1 \leq q \leq 200,000$
• $-1,000,000,000 \leq x \leq 1,000,000,000$

## Sample Input 1

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


## Sample Output 1

3
5
2