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()
copy = data
index = data.find("AB")
flag = 0
if index == -1:
    flag = 1
else:
    data = data[:index] + data[index + 2:]
    index = data.find("BA")
    if index == -1:
        flag = 1
    else:
        print("YES")

if flag:
    index = copy.find("BA")
    flag = 0
    if index == -1:
        flag = 1
    else:
        copy = copy[:index] + copy[index + 2:]
        index = copy.find("AB")
        if index == -1:
            flag = 1
        else:
            print("YES")

if flag: print("NO")
