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.
a=input()
n=a.split("AB",1)
r=a.split("BA",1)
if len(n)>1 and "BA" in n[1]:
  print ("YES")
elif len(r)>1 and "AB" in r[1]:
  print ("YES")
else:
  print ("NO")