using System;

public class Program

{

    public static bool IsPrime(long number) 

    {

    if (number <= 1)

      return false;

    else 

        if (number % 2 == 0)

            return number == 2;

​

    long N = (long) (Math.Sqrt(number) + 0.5);

​

    for (int i = 3; i <= N; i += 2)

      if (number % i == 0)

        return false; 

​

    return true;

  }

    public static void Main()

    {

        Boolean myBoolean;

        int no;

        Console.WriteLine("Enter a number:");

        no = int.Parse(Console.ReadLine());

        myBoolean = IsPrime(no);

        Console.WriteLine("Boolean value is {0}", myBoolean);

        if (myBoolean == true)

          Console.WriteLine("the number {0} is prime", no);

                do

                {       

                    no=no+1;

                    myBoolean= IsPrime(no);                              

                 }while(myBoolean==false);      

                 Console.WriteLine("the next prime number is: {0}", no);

    }

}