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().split("AB")
w = []
for i in a:
    q = i.split("BA")
    w.append(q)
if len(w) > 1 and (len(w[0]) > 1 or len(w[1]) > 1):
    print("YES")
else:
    print("NO")
