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.
s = input().split('AB', maxsplit=1)
for i in range(len(s)):
    if "BA" in s[i]:
        print("YES")
        break
else:
    print("NO")