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:
///#define _GLIBCXX_DEBUG
#include<bits/stdc++.h>
using namespace std;
template <class A, class B> inline bool chmax(A &a, const B &b) { return b > a && (a = b, true); }
template <class A, class B> inline bool chmin(A &a, const B &b) { return b < a && (a = b, true); }
typedef long long ll;
typedef vector<int> vint;
typedef pair<int, int> pint;
typedef vector<long long> vlong;
typedef vector<string> vstring;
#define vpush(a,x) a.push_back(x);
#define rep(i, n) REP(i, 0, n)
#define all(v) v.begin(), v.end()
#define REP(i, x, n) for(int i = x; i < n; i++)
const int INF = 1 << 30;
const int dx[] = {1,0,-1,0,1,1,-1,-1};
const int dy[] = {0,-1,0,1,1,-1,-1,1};
#define stp(x)  setprecision(x)
const long double PI=3.14159265358979323846264338327950;
int main(){
  cin.tie(nullptr);
  ios::sync_with_stdio(false);
  int n,q;
  cin>>n>>q;
  vector<stack<int> > vs(n);

  rep(i,q){
    int tmp,t,x;
    cin>>tmp;
    if(tmp==0){
      cin>>t>>x;
      vs[t].push(x);
    }
    else if(tmp==1){
      cin>>t;
      if(vs[t].empty()){
        continue;
      }
      cout<<vs[t].top()<<'\n';
    }
    else{
      cin>>t;
      if(vs[t].empty()){
        continue;
      }
      vs[t].pop();
    }
  }
  
  return(0);
}