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()

idx1 = s.find("AB")
idx2 = -1
if idx1 != -1:
    idx2 = s.find("BA", idx1+2)

idx3 = s.find("BA")
idx4 = -1
if idx3 != -1:
    idx4 = s.find("AB", idx3+2)

if idx4 != -1 or idx2 != -1:
    print("YES")
else:
    print("NO")