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" and "ba") in a:
    if a.index("ab") < a.index("ba") - 1 or a.index("ab") > a.index("ba") + 1:
        print("YES")
    else:
        print("NO")
else:
    print("NO")
