az tsvey ducks are shvimen vayt nokh katshke tsvey ducks shvimen hinter nokh katshke un eyns katshke iz shvimen tsvishn tsvey ander ducks velkh iz der minimum numerirn fun ducks

If two ducks are swimming in front of another duck, two ducks swimming behind another duck, and one duck is swimming between two other ducks, what is the minimum number of ducks?