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()
if len(s) < 4:
    print("NO")
    exit()
ab = s.count("AB")
ba = s.count("BA")
if ab and ba and (ab>1 or ba>1):
    print("YES")
else:
    if s.count("BAB") or s.count("ABA"):
        print("NO")
    else:
        print("YES")