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.
ch=input()
i=0
while(i<len(ch)-3):
  if (ch[i:i+2]=='AB' and 'BA' in ch) or (ch[i:i+2]=='BA' and 'AB' in ch):
    print('YES')
    break
  i+=2
if i>=len(ch)-3: print('NO')