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()

# Ищем индексы первого вхождения "AB" и "BA"
ab_index = s.find("AB")
ba_index = s.find("BA")

# Если нашли и "AB" и "BA" и между ними есть хотя бы 2 символа, то выводим "YES", иначе "NO"
if ab_index != -1 and ba_index != -1 and abs(ab_index - ba_index) >= 2:
    print("YES")
else:
    # Попробуем поменять местами "AB" и "BA" и проверить снова
    s = s.replace("AB", "XY").replace("BA", "AB").replace("XY", "BA")
    ab_index = s.find("AB")
    ba_index = s.find("BA")
    if ab_index != -1 and ba_index != -1 and abs(ab_index - ba_index) >= 2:
        print("YES")
    else:
        print("NO")