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.
def contains_non_overlapping_substrings(s):
    found_ab, found_ba = False, False
    i = 0

    while i < len(s) - 1:
        if s[i:i + 2] == "AB":
            found_ab = True
            i += 2
        else:
            i += 1

    i = 0

    while i < len(s) - 1:
        if s[i:i + 2] == "BA":
            found_ba = True
            i += 2
        else:
            i += 1

    return found_ab and found_ba

# Input
s = input()

# Output
if contains_non_overlapping_substrings(s):
    print("YES")
else:
    print("NO")
   		    	 	 		  	 	  	   	  	