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>

#define INF (2e9)
#define FOR(i, a, b) for (ll (i) = (a); (i) < (b); ++(i))
#define REP(i, n) FOR(i, 0, n)

using namespace std;

template<class T>
bool chmax(T& a, const T& b) {
    if (a < b) {
        a = b;
        return true;
    }
    return false;
}

template<class T>
bool chmin(T& a, const T& b) {
    if (b < a) {
        a = b;
        return true;
    }
    return false;
}

using ll = long long;
using ld = long double;

#define ALL(x) (x).begin(), (x).end()
template<class T>
using vc = vector<T>;
using vi = vc<ll>;
using vvi = vc<vi>;

template<class T>
using va = valarray<T>;
using vad = va<ld>;
using vai = va<ll>;

vi Read(ll n) {
    auto      v = vi(n);
    for (auto i = std::size_t(0); i < n; ++i) {
        cin >> v[i];
    }
    return v;
}

template<class T>
void Dump(const T& A) {
    for (const auto& value : A)
        cout << value << "\n";
}

int main() {
    ll n, p;
    cin >> n >> p;

    auto v = vc<stack<int>>(n);

    REP(i, p) {
        int query, t;
        cin >> query >> t;

        if (query == 0) {
            int x;
            cin >> x;
            v[t].push(x);
        } else if (query == 1) {
            if (!v[t].empty()) cout << v[t].top() << endl;
        } else if (query == 2) {
            if (!v[t].empty()) v[t].pop();
        } else cout << "Error: query is not correct\n";
    }

    return 0;
}