#include <iostream>
#include <fstream>

#include <stack>

using namespace std;

typedef stack<int> si_t;
class MyStack{
public:
    MyStack(){
        _s = NULL;
        _n = 0;
    }

    MyStack(int n){
        _s = new si_t[n];
        _n = n;
    }

    ~MyStack(){
        delete [] _s;
    }

    void push(int t, int x){
        _s[t].push(x);
        return;
    }

    void top(int t){
        if(_s[t].empty()){
            return;
        }else{
            cout << _s[t].top() << endl;
            return;
        }
    }

    void pop(int t){
        if(_s[t].empty()){
            return;
        }else{
            _s[t].pop();
            return;
        }
    }
private:
    si_t *_s;
    int _n;
};

int main(){
    int n,q;
    cin >> n >> q;
    MyStack s(n);
    for(int i=0;i<q;i++){
        int query,t;
        cin >> query >> t;
        switch(query){
        case 0:
            int x;cin >> x;
            s.push(t,x);
            break;
        case 1:
            s.top(t);
            break;
        case 2:
            s.pop(t);
            break;
        default: break;    
        }
    }
}

### Prompt

Construct a Cpp code solution to the problem outlined:

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

### Response

```cpp
#include <iostream>
#include <fstream>

#include <stack>

using namespace std;

typedef stack<int> si_t;
class MyStack{
public:
    MyStack(){
        _s = NULL;
        _n = 0;
    }

    MyStack(int n){
        _s = new si_t[n];
        _n = n;
    }

    ~MyStack(){
        delete [] _s;
    }

    void push(int t, int x){
        _s[t].push(x);
        return;
    }

    void top(int t){
        if(_s[t].empty()){
            return;
        }else{
            cout << _s[t].top() << endl;
            return;
        }
    }

    void pop(int t){
        if(_s[t].empty()){
            return;
        }else{
            _s[t].pop();
            return;
        }
    }
private:
    si_t *_s;
    int _n;
};

int main(){
    int n,q;
    cin >> n >> q;
    MyStack s(n);
    for(int i=0;i<q;i++){
        int query,t;
        cin >> query >> t;
        switch(query){
        case 0:
            int x;cin >> x;
            s.push(t,x);
            break;
        case 1:
            s.top(t);
            break;
        case 2:
            s.pop(t);
            break;
        default: break;    
        }
    }
}

```