The ruling on doubt regarding the number of rak'ahs

Question:
Honorable Shaykh, this person asks and says: Does it happen that when I am masbuq (one who joins the prayer late) in the prayer, I become distracted and forget how many rak'ahs I caught up with and how many remain for me to make up? And I wonder, when I am certain that the people are three, should I refer to the person praying next to me if I am unsure about the number of rak'ahs?

Answer:
First, if this is a matter of waswas (whispers of doubt) and it frequently occurs to him, he should leave it and not be affected by it. But if it is an occasional matter and not constant, he should build upon certainty. If he is unsure about the number of rak'ahs, he builds upon certainty. So if he is unsure whether he prayed three or four, he makes it three. If he is unsure whether he prayed two or three in Maghrib, he makes it two, the minimum, and completes the prayer and performs sujud al-sahw (the prostration for forgetfulness). Yes.