Can you figure out this riddle that is driving everyone insane?

Can you figure out this riddle that is driving everyone insane?

Literally everyone at East Coast Radio can't figure out this riddle. Can you?

Help
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I have bags under my eyes because I haven't slept.

Why?

Because I've been up trying to work out the answer to this problem! 

It's one of those riddles that as soon as you read it - you will be fixated!

Where is the missing R1?

Please help me solve this problem before it drives me absolutely INSANE!

Riddle
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