Program to Count Lines in a String

/*
 * C# Program to Count Lines in a String
 */
using System;
using System.Text.RegularExpressions;
class Program
{
    static void Main()
    {
        long a = countstring("This is \n Sanfoundry\n Website");
        Console.WriteLine("Number of Lines in the String : {0}",a);
        Console.ReadLine();
    }
    static long countstring(string s)
    {
        long count = 1;
        int start = 0;
        while ((start = s.IndexOf('\n', start)) != -1)
        {
            count++;
            start++;
        }
        return count;
    }
}