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.
S = input()
x = S.find("AB")
y = S.find("BA")
for i in range(x + 2, len(S) - 1):
    if S[i:i+2] == "BA":
        print("YES")
        exit()
for i in range(y + 2, len(S) - 1):
    if S[i:i+2] == "AB":
        print("YES")
        exit()

print("NO")
