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()
x="AB"
y="AB"
if x in s and y in s:
    if (s.index(x)!=s.index(y)+1)and(s.index(y)!=s.index(x)+1)and (s.index(x)!=s.index(y)):
        print("YES")
    else:
        print("NO")
