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.
str = input()

idx1 = str.find("AB")
idx2 = str.find("BA", idx1 + 2)

if idx1 != -1 and idx2 != -1 and abs(idx1 - idx2) >= 2:
    print("YES")
else:
    idx2 = str.find("BA")
    idx1 = str.find("AB", idx2 + 2)

    if idx1 != -1 and idx2 != -1 and abs(idx1 - idx2) >= 2:
        print("YES")
    else:
        print("NO")
