python求助，一直WA

x=input();
x=int(x);
a,b=input();
if a+b is'AB'or'BA'or'BB':
    print=(x*0.8);
elif a+b is'BC'or'CB':
    print=(x*0.6);
elif a+b is'AC'or'CA'or'CC':
    print=(x*0.7);
else:
    print(x)

O.o