How many days of Ramadan (9 days according to Sudan or 10 days according to Egypt) must be made up after fasting 31 days due to the difference in the beginning of the month between the two countries?

The later Shafi'i jurists are of the view that whoever invalidates the fast of the last day (the 31st) of his fasting owes neither a make-up fast nor expiation, because fasting on this day is not obligatory except by way of coincidence (muwafaqah). However, if the invalidated day was the 30th, then both make-up and expiation are required.