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>

class STACK{
public:
    long* data;
    int   size, memory;
    STACK(){
        memory = 4;
        size = 0;
        data = new long[memory];
    }
    ~STACK(){
        delete[] data;
    }
    void push(long x){
        size++;
        if (size > memory){
            memory *= 2;
            long* tmp = (long*)realloc(data, memory * sizeof(long));
            data = tmp;
        }
        data[size - 1] = x;
    }
    void pop(){
        if (size == 0) return;
        data[--size] = 0;
        if (size * 2 <= memory && memory >= 4){
            memory /= 2;
            long* tmp = (long*)realloc(data, memory * sizeof(long));
            data = tmp;
        }
    }
    void top(){
        if (size == 0) return;
        std::cout << data[size - 1] << std::endl;
    }
};

int main(){
    int n, q;
    std::cin >> n >> q;
    STACK* s = new STACK[n];
    while(q--){
        int com, t;
        std::cin >> com >> t;
        if (com == 0){
            long x;
            std::cin >> x;
            s[t].push(x);
        }
        if (com == 1){
            s[t].top();
        }
        if (com == 2){
            s[t].pop();
        }
    }
}