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