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 JAVA):

Solution:
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.lang.*;

public class Main {
    public static void main(String args[]) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        
        String[] s = br.readLine().split(" ", 0);
        int n = Integer.parseInt(s[0]);
        int q = Integer.parseInt(s[1]);
        
        Stack[] stacks = new Stack[n];
        for (int i = 0; i < n; i++) {
            stacks[i] = new Stack();
        }
        
        String[] l;
        String command;
        int t, x;
        for (int i = 0; i < q; i++) {
            l = br.readLine().split(" ", 0);
            command = l[0];
            t = Integer.parseInt(l[1]);
            switch (command) {
                case "0":
                    x = Integer.parseInt(l[2]);
                    stacks[t].push(x);
                    break;
                case "1":
                    stacks[t].top();
                    break;
                case "2":
                    stacks[t].pop();
                    break;
            }
        }
    }
}

class Stack {
    ArrayList<Integer> a;
    
    Stack() {
        a = new ArrayList<Integer>();
    }
    
    void push(int x) {
        a.add(x);
    }
    
    void top() {
        int size = a.size();
        if (size != 0) {
            System.out.println(a.get(a.size() - 1));
        }
    }
    
    void pop() {
        int size = a.size();
        if (size != 0) {
            a.remove(a.size() - 1);
        }
    }
}