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.
d=str(input())
n=0
s=0
for i in range(len(d)-1):
    if d[i:i+2]=="AB":
        n+=1
    elif d[i:i+2]=="BA":
        s+=1

if n>0 and s>0:
    print("YES")
else:
    print("NO")