using System;

public class Program

{

    public static void Main()

    {

        Queue q = new Queue(5);

        q.Add(1);

                Console.WriteLine(q.Peek());        

        q.Add(2);

        q.Add(3);       

        Console.WriteLine(q.Remove());      

        Console.WriteLine(q.Remove());

        Console.WriteLine(q.Remove());

        q.Add(4);

        q.Add(5);       

        Console.WriteLine(q.Remove());

        Console.WriteLine(q.Remove());

        Console.WriteLine(q.Remove());

    }

}

​

public class Queue

{

    Stack s1;

    Stack s2;

    public Queue(int capacity)

    {

        s1 = new Stack(capacity);

        s2 = new Stack(capacity);

    }

    public void Add(int n)

    {

        s1.Push(n);

    }

    public int Remove()

    {

        if(s2.Peek() == -1)

        {

            if(s1.Peek() == -1) return -1;

            while(s1.Peek() != -1)

            {

                s2.Push(s1.Pop());

            }

        }

        return s2.Pop();

    }

    public int Peek()

    {

                if(s2.Peek() == -1)

        {

            if(s1.Peek() == -1) return -1;

            while(s1.Peek() != -1)

            {

                s2.Push(s1.Pop());

            }

        }

        return s2.Peek();

    }

}

​

public class Stack

{

    int size = 0;

    int rear = -1;

    int[] arr;

    public int Capacity {get;set;}

    public Stack(int capacity)

    {

        this.Capacity = capacity;

        arr = new int[capacity];

    }

    public void Push(int n)

    {

        if(size == Capacity)

        {

            Console.WriteLine("Too full");

            return;

        }

        size++;

        rear++;

        arr[rear] = n;

    }

    public int Pop()

    {

        if(size == 0) {

            return -1;

        }

        size--;

        int val = arr[rear];

        rear--;

        return val;

    }

    public int Peek()

    {

        if(size == 0) {

            return -1;

        }

        return arr[rear];

    }

}