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 int long long
using namespace std;
const int INF = 1e10;
const int ZERO = 0;

signed main() {
    int N,Q;
    cin >> N >> Q;
    vector<stack<int>> S(N);
    for(int i = 0;i < Q;i++) {
        int A;
        cin >> A;
        if(A == 0) {
            int B,C;
            cin >> B >> C;
            S[B].push(C);
        }
        else if(A == 1) {
            int B;
            cin >> B;
            if(S[B].empty() == false) {
                cout << S[B].top() << endl;
            }
        }
        else {
            int B;
            cin >> B;
            if(S[B].empty() == false) {
                S[B].pop();
            } 
        }
    }
}