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()
found_ab = False
found_ba = False
for i in range(len(string) - 1):
    if string[i:i+2] == "AB":
        found_ab = True
        if i < len(string) - 2 and string[i+2:].find("BA") != -1:
            print("YES")
            found_ba = True
            break
    if string[i:i+2] == "BA":
        found_ba = True
        if i < len(string) - 2 and string[i+2:].find("AB") != -1:
            print("YES")
            found_ab = True
            break

if not found_ab or not found_ba:
    print("NO")
