But this is inferred from official website's data.

According to the data, Fangfang is a sister, not a sister, but as naive as her sister. Feifei is a sister type, not to mention that Feifei is a sister, just as stable and generous as a sister.

However, every time Fangfang Feifei's parents call them, Fangfang is the first and Feifei is the last. According to common sense, it is polite to call my sister first. So, Fangfang is my sister and Feifei is my sister!

I hope I can help you! (* _ _ *) Hee hee ...