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 CPP):

Solution:
#include <iostream>
#include <vector>

int main() {
    int N, Q;
    std::cin >> N >> Q;
    std::vector<std::vector<int>> v(N);
    for (int q = 0; q < Q; ++q) {
        int t;
        std::cin >> t;
        if (t == 0) {
            int i, x;
            std::cin >> i >> x;
            v[i].push_back(x);
        } else if (t == 1) {
            int i;
            std::cin >> i;
            if (!v[i].empty()) std::cout << v[i].back() << std::endl;
        } else {
            int i;
            std::cin >> i;
            if (!v[i].empty()) v[i].pop_back();
        }
    }
    return 0;
}