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 <cstdio>
#include <cmath>
#include <cctype>
#include <string>
#include <vector>
#include <stack>
#include <queue>
#include <deque>
#include <list>
#include <algorithm>
#include <map>
#include <numeric>
#include <iomanip>

using namespace std;

/* typedef */

typedef long long ll;

/* constant */

const int INF = 1 << 30;
const int MAX = 100;
const int mod = 1000000007;
const double pi = 3.141592653589;
/* global variables */

/* function */

/* main */
int main() {

    int n; cin >> n;
    vector< stack<int> > v(n, stack<int>());
    int q; cin >> q;
    while (q--) {

        int op; cin >> op;
        int t; cin >> t;

        if (op == 0) {
            int x; cin >> x;
            v[t].push(x);

        }
        else if (op == 1) {
            if (v[t].empty())
                continue;
            cout << v[t].top() << '\n';
        }
        else {
            if (v[t].empty())
                continue;
            v[t].pop();
        }
    }
}