The Messenger of Allah ﷺ said, "The month is twenty-nine days." Shuba clapped his hands together three times, folding down his thumb on the third clap.Uqba said, "I believe he also said, 'And the month is thirty days,'" and he clapped his hands together three times.
حدثنا محمد بن جعفر حدثنا شعبة عن عقبة بن حريث سمعت
قال رسول الله ﷺ الشهر تسع وعشرون وطبق شعبة يديه ثلاث مرات وكسر الإبهام في الثالثة قال عقبة وأحسبه قال والشهر ثلاثون وطبق كفيه ثلاث مرات
Its chain of transmission is sahih. It is a repetition of 5017, and a longer version of it appears at 5453, see also 5182.