Stayman

After Stayman, opener should bid his lowest 4-card major, or bid diamonds if he has none, i.e.

After 1NT > 2C	After 2NT > 3C
Bid 2D in the absence of a 4-card major	Bid 3D in the absence of a 4-card major
Bid 2H with 4+ hearts	Bid 3H with 4+ hearts
Bid 2S with 4+ spades and without 4 hearts	Bid 3S with 4+ spades and without 4 hearts
Continuations	Continuations

After minor Stayman, opener should bid his better 4-card minor, or bid NT if he has none, i.e.

After 1NT > 2S	After 2NT > 3S
Bid 2NT in the absence of a 4-card major	Bid 3NT in the absence of a 4-card major
Bid 3C with 4+ clubs	Bid 4C with 4+ clubs
Bid 3D with 4+ diamonds	Bid 4D with 4+ diamonds
Continuations	Continuations