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()
if s.count("AB") > 1 and s.count("BA") or s.count("BA") > 1 and s.count("AB"):
    print ("YES")
else:
    if "AB" in s: 
        s_ = s[0:s.index("AB")] + s[s.index("AB") + 2:]
        if "BA" in s_: print ("YES")
        else: print ("NO")
    else: print ("NO")