What was the number of wives that Prophet Muhammad (saw) used to visit during the day and night according to the hadith narrated by Qatada?
 Narrated Qatada:                     Anas bin Malik said, "The Prophet used to visit all his wives in a round, during the day and night and they were eleven in number." I asked Anas, "Had the Prophet the strength for it?" Anas replied, "We used to say that the Prophet was given the strength of thirty (men)." And Sa`id said on the authority of Qatada that Anas had told him about nine wives only (not eleven).