#include<iostream>
#include<stack>
using namespace std;
class Queue{
stack<int>sp,ss;
public:
    void enqueue(int data){
        sp.push(data);
    }
    int dequeue(){
        if(sp.empty()&&ss.empty()){
            return -1 ;
        }
        if(ss.empty()){
            while(sp.size()!=1){
            ss.push(sp.top());
            sp.pop();
            }
        }
         int x=ss.top();
         ss.pop();
         return x;

    }
    int getFront(){
        return sp.top();
    }

};

int main(){
    Queue q;
    q.enqueue(1);
    q.enqueue(2);
    q.enqueue(3);
    q.enqueue(4);
    for(int i=0;i<4;i++){
        cout<<q.getFront()<<" ";
        q.dequeue();
    }

return 0;}