#include <iostream>
#include <queue>
#include <string>

using namespace std;

int main() {
	queue<int> q;
	
	string s;
	cin >> s;
	while (s != "exit") {
		if (s == "push") {
			int n;
			cin >> n;
			q.push(n);
			cout << "ok\n";
		} else if (s == "pop") {
			cout << q.front() << "\n";
			q.pop();
		} else if (s == "front") {
			cout << q.front() << "\n";
		} else if (s == "size") {
			cout << q.size() << "\n";
		} else if (s == "clear") {
			while (q.size() > 0) {
				q.pop();
			}
			cout << "ok\n";
		}
		
		cin >> s;
	}
	cout << "bye\n";
	
	return 0;
}