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;

typedef long long int ll;
typedef pair<int,int> P;

#define rep(i,n) for(int i=0;i<(n);++i)
#define repi(i,a,b) for(int i=int(a);i<(b);i++)
#define repr(i,b,a) for(int i=int(b);i>=(a);i--)
#define all(x) x.begin(),x.end()

const ll mod = 1e9+7;
const ll INF = 1e9;

ll gcd(ll a,ll b){return b?gcd(b,a%b):a;}
int dx[4]={1,0,-1,0};
int dy[4]={0,1,0,-1};
bool valid(int lx,int ux,int ly,int uy,int x,int y){
	return lx<=x&&x<ux&&ly<=y&&y<uy; 
}
ll power(ll x,ll p){
	if(p==0)return 1;
	ll res=power(x*x%mod,p/2);
	if(p%2==1)res=res*x%mod;
	return res;
}

int main()
{

	int n,q;
	cin>>n>>q;
	vector<stack<int>> st(n);

	while(q--){
		int i;
		cin>>i;
		if(i==0){
			int t,x;
			cin>>t>>x;
			st[t].push(x);
		}else if(i==1){
			int t;
			cin>>t;
			if(st[t].size()!=0)cout<<st[t].top()<<endl;
		}else{
			int t;
			cin>>t;
			if(!st[t].empty())st[t].pop();
		}
	}
	return 0;
}