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()
if len(a) > 3:
    if ("ABA" in a or "BAB" in a) and (a.count("AB") > 1 or a.count("BA") > 1):
        print("YES")
    elif ("ABA" in a and "BAB" in a):
        print("YES")
    elif ("ABA" not in a) and ("BAB" not in a) and ("BA" in a) and ("AB" in a):
        print("YES")
    else:
        print("NO")
else:
    print("NO")
