The bidding starts with:
East You West Partner
2♠ X 4 ♠ X
2 Spade was a weak two
Partners double showed values and two placed to play. You should be confident to find him with 4 Hearts, as he had bid 4 NT with both minors.
Unuckily, you are quite sure, that partner will not understand 4 Nt followed by 5 Heart as passable invitation for 6, so you need to decide now: 5 or 6?
I made it wrong of course, else, there had been no question.

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