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()

# Find the first occurrence of "AB" and search for "BA" after it
if "AB" in s and "BA" in s[s.index("AB") + 2:]:
    print('YES')
    exit()

# Find the first occurrence of "BA" and search for "AB" after it
if "BA" in s and "AB" in s[s.index("BA") + 2:]:
    print('YES')
    exit()

print('NO')
