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()

a = s.find("AB")
b = s[a + 2:].find("BA")
c = s.find("BA")
d = s[c + 2:].find("AB")

print("YES" if a >= 0 and b >= 0 or c >= 0 and d >= 0 else "NO")