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()
s1= x.find('AB')
s2= x.find('BA', s1+2)
s3= x.find('BA')
s4= x.find('AB', s3+2)

if s1 != -1 and s2 != -1:
    print("YES")
elif s3 != -1 and s4 != -1:
    print("YES")
else:
    print("NO")