#include <iostream>
#include <string>
using namespace std;

struct queue{
	int storage[100000];
	int start;
	int finish;
	queue(){
		start = 0;
		finish = 0;
	}

	void push(int n){
		storage[finish] = n;
		finish++;
	}

	int pop(){
		int a = storage[start];
		start++;
		return a;
	}

	int front(){
		return storage[start];
	}

	int size(){
		return finish - start;
	}

	string clear(){
		finish = 0;
		start = 0;
		return "ok";
	}

	string exit(){
		return "bye";
	}
};

int main() {
	string a;
	queue x;
	while(cin >> a){
		if(a == "push"){
			int n;
			cin >> n;
			x.push(n);
			cout << "ok" << endl;
		}
		if(a == "pop"){
			cout << x.pop() << endl;
		}
		if(a == "front"){
			cout << x.front() << endl;
		}
		if(a == "size"){
			cout << x.size() << endl;
		}
		if(a == "clear"){
			cout << x.clear() << endl;
		}
		if(a == "exit"){
			cout << x.exit() << endl;
			return 0;
		}
	}
	return 0;
}