Where should the prostration of forgetfulness (sujud al-sahw) be performed in the prayer of one who added an extra rak'ah and forgot to say "Subhana Rabbi al-A'la" in their prostration?

If one mistakenly adds an extra rak'ah (unit of prayer) and inadvertently reduces the number of tasbih (glorifications) in prostration, the sujud al-sahw (prostration of forgetfulness) should be performed before the taslim (salutation). This is the view of the Hanbalis and Malikis. If two or more instances of forgetfulness occur, whether of the same type or different types, two prostrations suffice for all of them before the taslim. As for the congregant (ma'mum), sujud al-sahw is not obligatory for him in this case, because the Imam bears it on his behalf.