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()

# Check if "AB" followed by "BA" exists
if "AB" in s[s.find("BA") + 2:]:
    print('YES')
    exit()

# Check if "BA" followed by "AB" exists
if "BA" in s[s.find("AB") + 2:]:
    print('YES')
    exit()

print('NO')
