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()
b=0
if "ABA" in s:
     b=1
if(b==1):
    print("NO")
    exit()
if("AB" in s and "BA" in s):
    b=1
  
if(b==1):
     print("YES")
else:
     print("NO")