ὑφ

From LSJ

μήτε δίκην δικάσῃς πρίν ἀμφοῖν μῦθον ἀκούσῃς → do not give your judgement until you have heard a speech on both sides

Source

Russian (Dvoretsky)

ὑφ: перед придых. гласными = ὑπο-.