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.
n=input()
x = max(n.find("ABA"),n.find("BAB"))
y = min(n.find("AB"),n.find("BA"))
if(y==-1 or x!=-1):
    print("NO")
else:
    print("YES")