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().strip()
found_ab = found_ba = False

# Check for "AB" substring
for i in range(len(s) - 1):
    if s[i:i+2] == "AB":
        found_ab = True
        break

# Check for "BA" substring (starting from the end of the string)
for i in range(len(s) - 1, 0, -1):
    if s[i-1:i+1] == "BA":
        found_ba = True
        break

if found_ab and found_ba:
    print("YES")
else:
    print("NO")
