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.
s = input()
ind_ab = []
ind_ba = []
found = False
for i in range(len(s) - 1):
    if s[i:i+2] == "AB":
        ind_ab.append(i + 1)
    if s[i:i+2] == "BA":
        ind_ba.append(i)

for j in range(len(ind_ab)):
    if ind_ab[j] not in ind_ba:
        found = True
        break
if found:
    print("YES")
else:
    print("NO")
