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()
BAB = False
BA = False
AB = False

flag = False
for i in range(len(s)-2):
    sub = s[i:i+3]
    if "BAB" in sub or "ABA" in sub:
        BAB = True
    elif "AB" in sub:
        AB = True
    elif "BA" in sub:
        BA = True
    
    if (BA and AB) or (BAB and AB) or (BAB and BA):
        flag = True

if flag:
    print("YES")
else:
    print("NO")