นักเรียนชื่อ CHRISSY NABOZNY มีครูกี่คน
How many teachers does the student named CHRISSY NABOZNY have?
df_teachers = pd.DataFrame(columns=['classroom']); df_list = pd.DataFrame(columns=['classroom', 'firstname', 'lastname'])
len(df_teachers[df_teachers['classroom'].isin(df_list[(df_list['firstname'] == 'CHRISSY') & (df_list['lastname'] == 'NABOZNY')]['classroom'])])