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.
ALPHABET = "cdefghijklmnopqrstuvwxyz"

def filter(input : str) -> str:
    filterd = input
    for l in ALPHABET:
        filterd = filterd.replace(l, "")
    return filterd

def take_input():
    data = input()
    data = data.lower()
    return data


data = take_input()
filtered = filter(data)
if len(filtered) % 2 == 0:
    print("YES")
else:
    print("NO") 