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<stack>
using namespace std;
const int N=1010;
int main()
{
    int T,Z;
    stack<int> s[N];
    cin>>Z>>T;
    while(T--)
    {
        int c;
        cin>>c;
        switch (c)
        {
            case 0:
        {
            int n,m;
            cin>>n>>m;
            s[n].push(m);
        }break;
        case 1:
        {
            int n;
            cin>>n;
            if(s[n].size())
            cout<<s[n].top()<<endl;
        }break;
        case 2:
        {
            int n;
            cin>>n;
            if(s[n].size())
            {
                s[n].pop();
            }
        }break;
        default: break;
        }
        
    }
}