Is it obligatory to fast if menstrual bleeding stops for four days and the white discharge does not appear, then the bleeding returns with the characteristics of menstrual blood, and is the fast of the days when the bleeding stopped valid?

Blood that returns and brownish discharge after purity during the menstrual period is considered menstruation. Fasting during the days of purity interspersed within the menstrual period is valid and does not need to be repeated. A ritual bath (ghusl) is obligatory after the cessation of the returning blood and any accompanying brownish discharge. Fasting for the days in which the blood returned must be made up, unless the total duration of the continuous blood, the preceding blood, and the purity between them exceeds fifteen days. If a woman sees purity after seeing blood at night and then sees brownish discharge, this discharge is not considered menstruation. However, if she does not see purity, then the brownish discharge is considered menstruation.