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.find('BA', a+2)
c = s.find('BA')
d = s.find('AB', c+2)

if (a != -1 and b != -1) or (c != -1 and d != -1):
    print("YES")
else:
    print("NO")
