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.
#yousef
a=input()
if len(a)>3:
   if ("ABA" or "BAB") in a and (a.count("AB")>1 or a.count("BA")>1):
       print("YES")
   elif ("ABA" and "BAB") in a:
       print("YES")
   elif ("ABA" not in a) and( "BAB" not in a) and ("BA" in a) and ( "AB" in a) :
       print("YES")
   else:
        print("NO")
else:
    print("NO")