I am having list of records through columns A & B of which a number of rows of same value repeating multiple times. How can I flagging them in Col C, like "O" for original, "D" for duplicate, "T" fir triplicate, "Q" for quadruplicate and "M" for more than 4 times.?

Col A Col B Col C
NAME VALUE OCCURANCE
ABC 10 O
BCD 20 O
BCA 10 O
CAD 15 O
ABC 10 D
CBA 25 O
ABC 10 T
BCD 20 D
EFG 30 O
ABC 10 Q
BCA 10 D
CAD 15 D
ABC 10 M
CAD 15 T
ABC 10 M


Help please. Thanks.!

-via135