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.
str=input()
x1=str.find("AB")
x2=str.find("BA",x1+2)
y1=str.find("BA")
y2=str.find("AB",y1+2)
if (x1!=-1 and x2!=-1) or (y1!=-1 and y2!=-1):
    print("YES")
else:
    print("NO")

