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()

ab = s.count("AB")
ba = s.count("BA")

aba = s.count("ABA")
bab = s.count("BAB")


if(ab==0 or ba==0):
    print("YES")
elif(ab and ba and (aba>=2 or bab>=2)):
    print("YES")
elif ab and ba and bab==0 and aba==0:
    print("YES")
else:
    print("NO")
   		 		 		 	 	  	 		  		 				