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.
#R
s = str(input())
if ("AB" in s):
    s.replace("AB", "", 1)
    if ("BA" in s):
        print("YES")
    else :
        print("NO")
else :
    print("NO")