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.
import re
a=input()
b=re.search(r"(.+)?AB(.+)?BA(.+)?",a)
c=re.search(r"(.+)?BA(.+)?AB(.+)?",a)
print("YES" if any([b,c]) else "NO")