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:
from collections import deque
from typing import List


if __name__ == "__main__":
    stack_num, query_num = map(lambda x: int(x), input().split())
    stacks: List[deque] = [deque() for _ in range(stack_num)]

    for _ in range(query_num):
        op, *value = map(lambda x: int(x), input().split())
        if (0 == op):
            stacks[value[0]].append(value[1])
        elif (1 == op):
            stack = stacks[value[0]]
            if (0 != len(stack)):
                print(stack[len(stack) - 1])
        elif (2 == op):
            stack = stacks[value[0]]
            if (0 != len(stack)):
                stack.pop()
        else:
            pass