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.
a=input()
n=len(a)
ans='NO'
for i in range(n) :
    if a[i]!=a[n-1-i]:
        ans='YES'
        break
print(ans)