C#: Check Prime Number !

//Write program with Console Application type, enter the number N from the keyboard. Check whether n is prime no.
Source code:

class Program{

        static void Main(string[] args)

        {

            int n;

            bool prime = true;

            Console.Write("Input n: ");

            n = int.Parse(Console.ReadLine());           

            if (n <= 1) prime = false;

            else {

                if (n == 2) prime = true;

                for (int i = 2; i <= Math.Sqrt(n); i++)

                    if (n % i == 0) { prime = false; break; }

                    else prime = true;

            }

            if (prime == true) Console.WriteLine("{0} is prime no",n);

            else Console.WriteLine("{0} is not prime number", n);

            Console.ReadLine();

        }

    }