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()

one = False
two = False
z = s.find("AB")

for i in range(z + 2, len(s) - 1):
    x = s[i:i + 2]
    if x == "BA":
        one = True
        break  # Exit the loop after finding "BA"

z = s.find("BA")

for i in range(z + 2, len(s) - 1):
    x = s[i:i + 2]
    if x == "AB":
        two = True
        break  # Exit the loop after finding "AB"

if one or two:
    print("YES")
else:
    print("NO")
