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.
x = input()
if 'AB' in x and 'BA' in x:
    for i in range(len(x) - 1):
        if x[i] == 'B' and x[i - 1] == 'A' and x[i + 1] == 'A':
            print('NO')
            break
    else:
        print('YES')
else:
    print('NO')