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()
m=s.find("AB")
n=s.find("BA")
if(m+1==n or m==n):
    print("NO")
else :
    print("YES")