Stayman after Notrump/Maltais
After a one notrump opening and opponents' overcall, partner may bid Stayman by bidding the CHEAPEST minor available. Thus, after a
2C overcall = 2D is Stayman, and 2NT is the denial response
2D overcall = 3C is Stayman, and 3d denies a four card major.
After 2H, 2S overcall, responder bids longer minor to show length in that suit and the unbid major as well.
It should be noted that the more modern version of Stayman in this situation uses a cue bid of the overcalled suit as Stayman. This has been incorporated