Abu Salamah (may Allah have mercy on him) says that I asked Hazrat Aisha (may Allah be pleased with her), "Mother! How many rak'ahs did the Prophet (peace be upon him) pray after the 'Isha prayer?" She replied, "He used to pray four rak'ahs standing, two rak'ahs sitting, and two rak'ahs between the adhan and iqamah of Fajr."