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:
def solve():
    from sys import stdin
    f_i = stdin
    
    n, q = map(int, f_i.readline().split())
    S = [[] for i in range(n)]
    ans = []
    
    for i in range(q):
        query = f_i.readline()
        op = query[0]
        if op == '0':
            t, x = query[2:].split()
            S[int(t)].append(x)
            continue
        s = S[int(query[2:])]
        if s:
            if op == '1':
                ans.append(s[-1])
            else:
                s.pop()
    
    print('\n'.join(ans))

solve()