P

#include <iostream>
#include <vector>

using namespace std;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    unsigned n, p, c;
    vector<unsigned> b;
    vector<string> answer;

    cin >> n;
    p = 1;
    for (unsigned i = 0; i < n; ++i) {
        cin >> c;
        answer.push_back("push");
        if (c == p) {
            answer.push_back("pop");
            ++p;
        } else {
            b.push_back(c);
        }
        while (b.size() > 0 && *b.rbegin() == p) {
            b.pop_back();
            answer.push_back("pop");
            ++p;
        }
    }

    if (p != n + 1) {
        cout << "impossible" << endl;
    } else {
        for (string action: answer) {
            cout << action << endl;
        }
    }
}