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()
found = False

# Check for non-overlapping "AB" and "BA" substrings
if "AB" in s:
    index = s.index("AB")
    if "BA" in s[index + 2:]:
        found = True

if not found and "BA" in s:
    index = s.index("BA")
    if "AB" in s[index + 2:]:
        found = True

if found:
    print("YES")
else:
    print("NO")
