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.
word = input()

if len(word) < 3:
    print('NO')
else:
    out = []
    for i in (('AB', 'BA'), ('BA', 'AB')):
        i1 = word.find(i[0])
        i2 = word.rfind(i[1])

        if -1 in (i1, i2):
            out.append(False)
        else:
            out.append(abs(i1 - i2) >= 2)

    print('YES' if any(out) else 'NO')
