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()
try:
    if "BA" in s[s.index("AB") + 2 :]:
        print("YES")
        exit()
    elif "AB" in s[s.index("BA") + 2 :]:
        print("YES")
        exit()
except :
    pass
 
print("NO")