768
Sahih+3
Abdullah bin Shaqiq narrated:"I asked Aishah about the Prophet's fasting.' She said: 'He would fast until we said: "He has fasted" and he would abstain from fasting until we said: "He has abstained from fasting." (She said:) 'The Messenger of Allah did not fast an entire month except Ramadan
SahihAhmad Muhammad Shakir
SahihAl-Albani