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 containsTwoSubstrings(s):
    ab_index = s.find("AB")
    
    if ab_index != -1:
        ba_index = s.find("BA", ab_index + 2)
        
        if ba_index != -1:
            return "YES"
    
    ba_index = s.find("BA")
    
    if ba_index != -1:
        ab_index = s.find("AB", ba_index + 2)
        
        if ab_index != -1:
            return "YES"
    
    return "NO"

s = input()
result = containsTwoSubstrings(s)
print(result)

	 			 	      		 	 		         	