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.
def decomp(s):
    parts = []
    i = 0
    while i < len(s):
        if s[i] not in ('A', 'B'):
            i += 1
            continue
        k = i + 1
        while k < len(s):
            if s[k] in ('A', 'B'):
                k += 1
            else:
                break
        parts.append(s[i:k])
        i = k
    return parts


def solve(s):
    p = decomp(s)
    return 'AB' in p and 'BA' in p

s = input()
if solve(s):
    print("YES")
else:
    print("NO")
