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()

# Find the first occurrence of "AB"
index_ab = s.find("AB")

# Check if "BA" occurs after the first "AB"
if index_ab != -1 and s.find("BA", index_ab + 2) != -1:
    print("YES")
else:
    # Find the first occurrence of "BA"
    index_ba = s.find("BA")
    
    # Check if "AB" occurs after the first "BA"
    if index_ba != -1 and s.find("AB", index_ba + 2) != -1:
        print("YES")
    else:
        print("NO")
