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.
__author__ = 'OnePiece'

def main():
    s = input()
    for i in range(len(s)):
        if ("AB" in s[:i] and "BA" in s[i + 1:]) or ("BA" in s[:i] and "AB" in s[i + 1:]):
            print("YES")
            return
    print("NO")

if __name__ == '__main__':
    main()
