24 23 21 bytes
u # Convert the input to uppercase. •éÓœ°D¥M™ù>•30B # Compressed version of CHDDFFNGLLPHRHTH. It convert the text between the •'s from base 214 to base 10 and converts that to base 30. 2ô # Split into pieces of 2. 0: # Replace each element that also occurs in the input by 0. g # Get the length of the processed input.
Uses the CP-1252 encoding. Try it online!