count how many times selected columns have same value plus a range in pandas

Question

I have this dataframe:

,A,B,C,A2,B2,C2
2018-12-01,7,0,8,17,17,17
2018-12-02,0,0,8,20,18,18
2018-12-03,9,8,8,17,17,18
2018-12-04,8,8,8,17,17,18
2018-12-05,8,8,8,17