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.
string = input()
flag_ab = False
flag_ba = False

for i in range(len(string) - 1):
    if string[i:i+2] == "AB":
        flag_ab = True
        if flag_ba:
            print("YES")
            exit()
    elif string[i:i+2] == "BA":
        flag_ba = True
        if flag_ab:
            print("YES")
            exit()

print("NO")
