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.
# Wadea #

s = list(input())
ss = s.copy()
r = 0
for i in range(len(s)-1):
    if s[i] == "A" and s[i] == "B":
        r += 1
        s[i] = ""
        s[i+1] = ""
        s = "".join(s)
        if "BA" in s:
            print("YES")
            break
for i in range(len(s)-1):
    if ss[i] == "B" and ss[i] == "A":
        r += 1
        ss[i] = ""
        ss[i+1] = ""
        ss = "".join(ss)
        if "BA" in ss:
            print("YES")
            break
if r == 0:
    print("NO")