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

# Check for the first occurrence of "AB" and "BA"
for i in range(len(s) - 1):
    if s[i:i+2] == "AB" and not ba_found:
        ab_found = True
    elif s[i:i+2] == "BA" and not ab_found:
        ba_found = True

# Check if both "AB" and "BA" are found
if ab_found and ba_found:
    print("YES")
else:
    ab_found = False
    ba_found = False

    # Check for the first occurrence of "BA" and "AB"
    for i in range(len(s) - 1):
        if s[i:i+2] == "BA" and not ab_found:
            ba_found = True
        elif s[i:i+2] == "AB" and not ba_found:
            ab_found = True

    # Check if both "BA" and "AB" are found
    if ab_found and ba_found:
        print("YES")
    else:
        print("NO")
