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 <bits/stdc++.h>
#define rep(i,a,b) for (int i = (a); i < (b); i++)
#define REP(i,n) rep(i,0,n)
using namespace std;

int main()
{  
    int n,q;
    cin>>n>>q;
    vector<vector<int>>a(n);
    REP(i,q)
    {
        int x,y;
        cin>>x>>y;
        if(x==0)
        {
            int z;
            cin>>z;
            a.at(y).push_back(z);
        }else if(x==1)
        {
            if(a.at(y).empty()==0)cout<<a.at(y).back()<<endl;
        }else if(x==2)
        {
            if(a.at(y).empty()==0)a.at(y).pop_back();
        }
    }
}