Is it obligatory to feed a needy person for the days I missed fasting in Ramadan due to menstruation, and what is the amount of feeding if I do not remember the number of days?

Ramadan fasts must be made up before the next Ramadan. It is not permissible to delay making them up without a valid excuse. If someone delays making up the fasts without a valid excuse until the next Ramadan begins, they must, in addition to making up the fasts, pay a fidyah (expiation) for each day, which is feeding one poor person for each day. The fidyah is obligatory from the asset of the one who owes the fasts. If they are unable to pay, it remains a debt upon them and should be paid whenever they become able to do so. The amount of food to be given is one mudd for each poor person from the staple food commonly eaten. However, if the delay was due to a valid excuse, then the fidyah is not obligatory.