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()

# Search for "AB" and "BA" from left to right
if "AB" in s and s[s.index("AB") + 2:].find("BA") != -1:
    print("YES")
# Search for "BA" and "AB" from left to right
elif "BA" in s and s[s.index("BA") + 2:].find("AB") != -1:
    print("YES")
else:
    print("NO")

    					     		 	  				     	