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.
# /**
#  *     author: brownfox2k6
#  *    created: 28/05/2023 01:23:51 Hanoi, Vietnam
# **/

s = input()

try:
    if "BA" in s[s.index("AB") + 2 :]:
        exit(print("YES"))
except ValueError:
    try:
        if "AB" in s[s.index("BA") + 2 :]:
            exit(print("YES"))
    except ValueError:
        pass

print("NO")