Is fasting valid on the two days when a small amount of pinkish blood spots appeared, knowing that the last menstrual period exceeded fifteen days?

If the previous menstrual period exceeded fifteen days, then the woman is in a state of istihadah (non-menstrual bleeding). She must refer to her previous habit, or distinguish (between menstrual and non-menstrual blood) if she is able to, or by estimation, considering six or seven days of each month as menstruation. Accordingly, if she saw blood during the time of her menstruation, she must make up the fast of the two days. If it was during the time of istihadah, her fast is valid, and she is not required to make it up.