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()
ans = ''
l = []

if 'ab' in s and 'ba' in s:
    idx_ab = s.index('ab')
    idx_ba = s.index('ba')
    
    # Check if the two substrings are non-overlapping
    if abs(idx_ab - idx_ba) > 1:
        l.append('YES')
    else:
        l.append('NO')
else:
    l.append('NO')

if 'YES' in l:
    print('YES')
else:
    print('NO')
