Doubt after the Salam

1188. If a person becomes doubtful after the Salam of prayers, as to whether or not he has offered the prayers correctly, like, if he doubts whether or not he has performed the Ruku’, or doubts in a 4 Rak’at prayers as to whether he has performed 4 or 5 Rak’ats, he should ignore his doubt. But if both sides of the doubt lead to invalidity of the prayers like, if he doubts in 4 Rak’at prayers whether he has performed 3 or 5 Rak’ats, his prayers would be void.