This sentence has been a bit tricky for me:
τὸ μὲν μὴ ἀγανακτεῖν, ὦ ἄνδρες Ἀθηναῖοι, ἐπὶ τούτῳ τῷ γεγονότι, ὅτι μου κατεψηφίσασθε, ἄλλα τέ μοι πολλὰ συμβάλλεται, καὶ οὐκ ἀνέλπιστόν μοι γέγονεν τὸ γεγονὸς τοῦτο, ἀλλὰ πολὺ μᾶλλον θαυμάζω ἑκατέρων τῶν ψήφων τὸν γεγονότα ἀριθμόν.
I'm especially confused by the μὲν. I can't grasp the nuances of why it would appear in this context. Denniston unfortunately doesn't discuss this instance.