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.
# Wadea #

s = input()
ans = "NO"
if "AB" in s:
    a = s.replace("AB"," ",1)
    if "BA" in a:
        ans = "YES"

if "BA" in s:
    s = s.replace("BA"," ",1)
    if "AB" in s:
        ans = "YES"
print(ans) 

    