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.
st = input()
ab = st.count("AB")
ba = st.count("BA")
aba = st.count("ABA")
print("NO") if ab==0 and ba==0 or aba!=0 else print("YES")
# print("NO" if ab==0 and ba == 0 and aba!=0)
