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 = list(input())
for i in range(len(s)-1):
    if s[i] == "A" and s[i+1] == "B":
        s.remove(s[i])
        s.remove(s[i])
        break
t = ''
for i in s:
    t += i
if "AB" in t:
    print('YES')
else:
    print("NO")
