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;
using lint = long long;
template<typename T = lint>inline T in() { T x; cin >> x; return x; }
#define INF           1e9
#define INFL          static_cast<lint>(INF)
#define REP(i,n)      for(lint i=0,i##_len=(n);i<i##_len;++i)
#define REP1(i,n)     for(lint i=1,i##_len=(n);i<=i##_len;++i)
#define REPI(i,ini,n) for(lint i=(ini),i##_len=(n);i<i##_len;++i)
#define REPC(i,obj)   for(auto i:obj)
#define R_UP(a,b)     (((a)+(b)-1)/(b))
#define ALL(obj)      (obj).begin(),(obj).end()
int main()
{
	int n = in(), q = in();
	vector<stack<int>>s(n);
	REP(i, q)
	{
		int t, x;
		switch (in())
		{
		case 0:
			t = in(), x = in();
			s[t].push(x);
			break;
		case 1:
			t = in();
			if (s[t].size() != 0)cout << s[t].top() << endl;
			break;
		case 2:
			t = in();
			if (s[t].size() != 0)s[t].pop();
			break;
		}
	}
}