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()
try:
  x=a.index("AB")
  y=a.index("BA")
  if x-y>1 or x-y<-1:
      print("YES")
  else: print("NO")
except:
  print("NO")
