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.
s=input()
i1=s.count("AB")
i2=s.count("BA")
i3=s.count("ABA")
i4=s.count("BAB")
i5=s.count("BABA")
i6=s.count("ABAB")
if i5 or i6:
  print("YES")
elif i1>1 and i2>1:
  print("YES")
elif i1==1 and i2>1:
  print("YES")
elif i1>1 and i2==1:
  print("YES")
elif i1==1 and i2==1 and i3==0 and i4==0:
  print("YES")
else :
  print("NO")
  