public static void Main()
Console.WriteLine("Enter first string: ");
string input1 = Console.ReadLine();
Console.WriteLine("Enter second string: ");
string input2 = Console.ReadLine();
input1 = input1.ToLower();
input2 = input2.ToLower();
Console.WriteLine("Equal");
Console.WriteLine("Not Equal");
string str = "Celebrating 200 year of Indiana University";
int idx1 = str.IndexOf("r");
int idx2 = str.IndexOf("r", idx1 + 1);
str = str.Insert(idx2 + 1, "s");