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()
ABl = s.find("AB"); ABr = s.rfind("AB")
BAl = s.find("BA"); BAr = s.rfind("BA")

if abs(BAr - ABl) > 1: print("YES")
elif abs(ABr - BAl) > 1: print("YES")
else: print("NO")