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.
def main():
    s = input()
    AB_cnt = s.count("AB")
    BA_cnt = s.count("BA")
    ABA_cnt = s.count("ABA")

    if AB_cnt + BA_cnt - ABA_cnt >= 2:
        print("YES")
    else:
        print("NO")


main()
