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()

ab_found = False
ba_found = False
found = False

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

# Check if "BA" exists
for i in range(len(s) - 1):
    if s[i:i+2] == 'BA':
        ba_found = True
        break

# Check if both substrings exist and their positions are not adjacent
if ab_found and ba_found and abs(s.index('AB') - s.index('BA')) > 1:
    found = True

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