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 = str(input())
q, w = [], []
if len(a) % 2 == 1: a += "00"
for i in range(0, len(a), 2):
 q.append(a[i:i+2])
for i in range(1, len(a), 2):
 w.append(a[i:i+2])
print("YES") if ("AB" in q and "BA" in q) or ("AB" in w and "BA" in w) else print("NO")