18: Add solution for "quiz3".

Created by  Aaw9nJhsNmfzFih9mKyNw9mV8CgERXJkRa1kK1Kx3LQH  on August 7, 2021
JBU7ITG4WFYNXLK3KL6BTQ4DXP7NDRPBGKYWNJX3Z6FT4HIA63PQC
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