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().casefold()
found = False

# Check if "AB" followed by "BA" exists
for i in range(len(s) - 1):
    if s[i:i+2] == 'ab' and 'ba' in s[i+2:]:
        found = True
        break

# If not found, check if "BA" followed by "AB" exists
if not found:
    for i in range(len(s) - 1):
        if s[i:i+2] == 'ba' and 'ab' in s[i+2:]:
            found = True
            break

if found:
    print('YES')
else:
    print('NO')
