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:
import sys
from collections import deque
n, q = map(int, input().split())

deq = deque()
arrays = {str(i): deque() for i in range(n)}

lines = sys.stdin.readlines()
for i in range(q):
    query, *arg = lines[i].split()
    if query == '0':    # push t x
        arrays[arg[0]].append(arg[1])
    elif query == '1':  # top
        if len(arrays[arg[0]]):
            print(arrays[arg[0]][-1])
    elif query == '2':  # pop
        if len(arrays[arg[0]]):
            arrays[arg[0]].pop()
    else:
        raise AssertionError