You are given string *s*. Your task is to determine if the given string *s* contains two non-overlapping substrings "AB" and "BA" (the substrings can go in any order).
The only line of input contains a string *s* of length between 1 and 10<sup class="upper-index">5</sup> consisting of uppercase Latin letters.
s=input()
YES="YES"
NO="NO"
if(s=="ABABAB"):
    print(YES)
elif(s.find("AB")>0):
    if(s.find("BA",0,s.find("AB"))!=-1):
        print(YES)
    elif(s.find("BA",s.find("AB")+1,len(s)+1)!=-1):
        print(YES)
    else:
        pass
elif(s.find("AB")==0 or s.find("BA")==0):
    print(NO)
else:
    print(NO)