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 Stack:

  def __init__(self):
    self.S = list()

  #0:insert
  def push(self,x):
    self.S.append(x)

  #1:top
  def top(self):
    if len(self.S) > 0:
      print(self.S[-1])
      
  #2:erase
  def pop(self):
    if len(self.S) > 0:
      self.S.pop()

n,q = map(int,input().split())
SList = list()

for i in range(n):
  SList.append(Stack())

for i in range(q):
  cmd = input()
  
  if cmd.startswith("0"):
    c,t,x = map(int,cmd.split(" "))
    SList[t].push(x)
    
  if cmd.startswith("1"):
    c,t = map(int,cmd.split(" "))
    SList[t].top()
  
  if cmd.startswith("2"):
    c,t = map(int,cmd.split(" "))
    SList[t].pop()