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 solve(s):
    if len(s)<=3:
        return False
    if ("AB" not in s ) or ("BA" not in s ):
        return False
    if (s.find("AB")+1<s.find("BA")) or (s.find("BA")+1<s.find("AB")):
        return True



s=str(input())
if solve(s):
    print("YES")
else:
    print("NO")