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()
yes = False
for i in range(len(s)-1):
    if s[i] == "A" and s[i+1] == "B":
        if "BA" in s[i+2:]:
            yes = True
        if "BA" in s[:i]:
            yes = True
if not yes:
    print("NO")
else:
    print('YES') 
