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>
using namespace std;
int main() {
    int n,q,a,t,x;
    cin >> n;
    vector<vector<int>> vec(n,vector<int>());
    cin >> q;
    for (int i=0;i<q;i++) {
        cin >> a >> t;
        if ( a==0 ) {
            cin >> x;
            vec[t].emplace_back(x);
//            cout << vec[t].size() << endl;
        } else if ( a==1 ) {
            if ( vec[t].empty()!=true ) {
                cout << vec[t][vec[t].size()-1] << endl;
            }
        } else if ( a==2 ) {
            if ( vec[t].empty()!=true ) {
                vec[t].pop_back();
                vec.shrink_to_fit();
            }
        }
    }
}