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 main():
    s = input().strip()
    ab = s.find("AB")
    ba = s.find("BA", ab + 2)
    if ba == -1:
        ba = s.find("BA")
        ab = s.find("AB", ba + 2)
    if ab != -1 and ba != -1:
        print("YES")
    else:
        print("NO")

if __name__ == "__main__":
    main()
