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()

index_ab = s.find("AB")
index_ba = s.find("BA", index_ab + 2)

index_ba_2 = s.find("BA")
index_ab_2 = s.find("AB", index_ba_2 + 2)

if index_ab != -1 and index_ba != -1:
    print("YES")
elif index_ab_2 != -1 and index_ba_2 != -1:
    print("YES")
else:
    print("NO")