public static void Main()
Console.WriteLine("Enter your first string");
string str1 = Console.ReadLine();
Console.WriteLine("Enter your second string");
string str2 = Console.ReadLine();
{ Console.WriteLine("Equal");
{ Console.WriteLine("Not Equal");
string str3 = "Celebrating 200 year of Indiana University";
int year_postion = str3.IndexOf("year");
str3= str3.Insert(year_postion +4 ,"s");