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 ll=long long;
using namespace std;

#define rep_i(i, n) for (int i = 0; i < (n); ++i)
#define rep_ll(i, n) for (long long i = 0; i < (n); ++i)
#define r_rep_i(i, start, end) for (int i = (start); i < (end); ++i)
#define r_rep_ll(i, start, end) for (long long i = (start); i < (end); ++i)
#define debug_vi(v) copy((v).begin(), (v).end(), ostream_iterator<int>(cout, " "));
#define debug_vll(v) copy((v).begin(), (v).end(), ostream_iterator<long long>(cout, " "));
#define debug_vd(v) copy((v).begin(), (v).end(), ostream_iterator<double>(cout, " "));
#define sort_v(v) sort((v).begin(), (v).end()); //昇順
#define d_sort_vi(v) sort((v).begin(), (v).end(), greater<int>()); //降
#define d_sort_vll(v) sort((v).begin(), (v).end(), greater<long long>()); //降
#define d_sort_vd(v) sort((v).begin(), (v).end(), greater<double>()); //昇順
#define say(t) cout << (t) << endl;
#define sum_vi(v) accumulate((v).begin(), (v).end(), 0);
#define sum_vll(v)accumulate((v).begin(), (v).end(), 0LL);

ll gcd(ll a, ll b) { return b?gcd(b, a%b):a;}
ll lcm(ll a, ll b) { return a/gcd(a, b)*b;}

const int IINF=(1<<30);
const ll LLINF = 1LL<<60;

char BigAlphaToSmall(char a){
    if (a >= 65 && a <= 90){
        return a + 32;
    }
    return a;
}

char SmallAlphaToBig(char a){
    if (a >= 97 && a <= 122){
        return a - 32;
    }
    return a;
}

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    int n, q;cin >> n >> q;
    vector<stack<int>> hoge(n);

    int a, b, c;
    rep_i(i, q){
        cin >> a;
        if(a == 0){
            cin >> b >> c;
            hoge[b].push(c);
            continue;
        }

        if(a == 1){
            cin >> b;
            if(hoge[b].empty()) continue;
            say(hoge[b].top())
            continue;
        }

        if(a == 2){
            cin >> b;
            if(hoge[b].empty()) continue;
            hoge[b].pop();
            continue;
        }
    }
}