public static void Main()
Console.WriteLine("Input first string.");
string FirstStr = Console.ReadLine();
Console.WriteLine("Input second string.");
string SecondStr = Console.ReadLine();
string TrimFirst = FirstStr.Trim();
string TrimSecond = FirstStr.Trim();
string UpperFirst = TrimFirst.ToUpper();
string UpperSecond = TrimSecond.ToUpper();
bool StringEqual = TrimFirst.Contains(TrimSecond);
Console.WriteLine("Equal");
else if (StringEqual == false)
Console.WriteLine("Not equal");
string strCelebration = "Celebrating 200 year of Indiana University";
int intFirstSpace = strCelebration.IndexOf(" ");
int intSecondSpace = strCelebration.IndexOf(" ",intFirstSpace + 1);
int intThirdSpace = strCelebration.IndexOf(" ",intSecondSpace + 1);
string strCelebration2 = strCelebration.Insert(intThirdSpace,"s");
Console.WriteLine(strCelebration2);