Python, score 49

lambda S:sum(1+S.count(C)for[C]in	S)/2

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Score breakdown:

• 38 total chars
• +8 extra points for ()Camnou appearing twice
• +3 extra points for S appearing 3 times.

Python, score 49

lambda S:sum(1+S.count(C)for[C]in	S)/2

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Score breakdown:

• +27 for 27 unique chars
• +16 for 8 double chars: ()Camnou
• +6 for 1 tripled char: S

Python, score 49

lambda S:sum(1+S.count(C)for[C]in	S)/2

Try it online!

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Score breakdown:

• 38 total chars, 27 unique
• +8 extra for ()Camnou appearing twice
• +3 for S appearing 3 times.

Python, score 49

lambda S:sum(1+S.count(C)for[C]in	S)/2

Try it online!

There's a tab after in.

Score breakdown:

• 38 total chars
• +8 extra points for ()Camnou appearing twice
• +3 extra points for S appearing 3 times.

Python, score 49

lambda S:sum(1+S.count(C)for[C]in	S)/2

Try it online!

There's a tab after in.

Python, score 49

lambda S:sum(1+S.count(C)for[C]in	S)/2

Try it online!

There's a tab after in.

Score breakdown:

• 38 total chars, 27 unique
• +8 extra for ()Camnou appearing twice
• +3 for S appearing 3 times.