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.find("AB")!=-1):
    s=s.replace("AB","",1)
    if(s.find("BA")!=-1):
        print("YES")
    else:
        print(NO)
else:
    print(NO)