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.
x = input()
k = len(x)
l = []
for i in range(k-1):
  temp = x[i] + x[i+1]
  if temp == 'AB' or temp == 'BA':
    l.append(i)
k = len(l)
if k == 0:
  print("NO")
else:
  yes = 1
  for i in range(k-1):
    if l[i+1] - l[i] == 1:
      yes = 0
      break
  if yes:
    print("YES")
  else:
    print("NO")