template <typename Type>
class Queue{
public:
    void Push(const Type &element){
        if(stack1_.empty()){
            stack1_.push(element);
            return;
        }
    }
    void Pop(){
        if(!stack1_.empty()){
            Type last_elem = stack1_.top();
            if(last_elem < stack2_.top()){
                //stack1_.pop();
                //Push(last_elem);
                stack2_.push(last_elem);
            } else{
                stack1_.push(stack2_.top());
            }
        }
    }
    Type &Front(){
        if(!stack2_.empty()){
            Type last_elem = stack2_.top();
            if(last_elem < stack1_.top()){
                //stack2_.pop();
                //Push(last_elem);
                stack1_.push(last_elem);
                return stack1_.top();
            } else{
                stack2_.push(stack1_.top());
                return stack2_.top();
            }
        }else{
            return stack1_.top();
        }
    }
    uint64_t Size() const{return stack1_.size() + stack2_.size();}
    bool IsEmpty() const{return stack1_.empty() && stack2_.empty();}

private:
    stack<Type> stack1_;
    stack<Type> stack2_;
};