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.
string = input()
flag = False

for i in range(len(string) - 1):
    if string[i:i+2] == "AB" and "BA" in string[i+2:]:
        flag = True
        break
    elif string[i:i+2] == "BA" and "AB" in string[i+2:]:
        flag = True
        break

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