Menu Selections
    ===============

    a - add son-father pair
    e - exit

Enter menu selection: qwerty
Invalid menu selection! Try agin.

Enter menu selection: 
Invalid menu selection! Try agin.

Enter menu selection: a
Son-father pair addition.
Enter son's name: JEFF
Doug is the father of Jeff

Enter menu selection: a
Son-father pair addition.
Enter son's name: bRuCe
Richard is the father of Bruce

Enter menu selection: a
Son-father pair addition.
Enter son's name: fred
Enter father's name: BILL

Enter menu selection: a
Son-father pair addition.
Enter son's name: FrEd
Bill is the father of Fred

Enter menu selection: e
Exiting ...
Done!