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.
data = input()


index = data.find("AB")


if index == -1:
    print("NO")
else:
    data = data[:index] + data[index + 2 :]


    index = data.find("BA")

    if index == -1:
        print("NO")
    else:
        print("YES")