If responder is weak, transfer to the five-card major and pass. Otherwise use a Stayman to show 5-4 in the majors as follows:
1NT — 2♣; 2♦:
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2♥ or 2♠: that major, invitational
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3♥ or 3♠: the other major, game-forcing
Over 2NT, a similar system applies but there are no invitational bids:
2NT — 3♣; 3♦:
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pass: weak (5-4=4=0 distribution)
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3♥ or 3♠: the other major, game-forcing
Smolen does not apply over 3NT.