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.
word = str(input())

abcount = word.count("AB")
bacount = word.count("BA")
abacount = word.count("ABA")


if abcount > 0 and bacount > 0 and len(word) > 3:
    print("YES")
else:
    if abacount >= 2:
        print("YES")
    # elif abs((abcount+bacount) - abacount) > 1:
    #     print("YES")
    else:
        print("NO")