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.
a = input().lower()
if "ab" in a and "ba" in a:
    index_ab = a.index("ab")
    index_ba = a.index("ba")
    if abs(index_ab - index_ba) >= 2:
        print("YES")
    else:
        print("NO")
else:
    print("NO")
