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;

void solve(stack<int> box[]){
    int x; cin >> x;
    switch(x){
        case 0:
            int t0, y; cin >> t0 >> y;
            box[t0].push(y);
            break;
        case 1:
            int t1; cin >> t1;
            if(!box[t1].empty()) cout << box[t1].top() << endl;
            break;
        case 2:
            int t2; cin >> t2;
            if(!box[t2].empty()) box[t2].pop();
            break;
        default: cout << "ERROR" << endl;
    }
}

int main(){
    int n, q; cin >> n >> q;
    stack<int> box[n];
    while(q--){
        solve(box);
    }
    return 0;
}