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.
n = input()
n1 = n.find("AB")
n2 = n.find("BA",n1+2)
n3 = n.find("BA")
n4 = n.find("AB",n3+2)
if n1 >= 0 and n2 >=0:
    print("yes")
elif n3 >= 0 and n4 >=0:
    print("yes")
else:
    print("no")