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.
# LUOGU_RID: 134402526
s=input()
a,b=[],[]
for i in range(len(s)-1):
  if s[i]=='A' and s[i+1]=='B':
    a.append(i)
  elif s[i]=='B' and s[i+1]=='A':
    b.append(i)
for i in a:
  for j in b:
    if abs(i-j)>1:
      print('YES')
      exit()
print('NO')