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.
s = input()
a =[]
b = []
c = set()
for i in range(len(s) - 1):
    if s[i] == "A" and s[i + 1] == "B":
        a.append(i)
    if s[i] == "B" and s[i + 1] == "A":
        b.append(i)
        
for i in range(len(a)):
    for j in range(len(b)):
        c.add(abs(a[i] - b[j]))

if len(c) > 0 and max(c) > 1:
    print("YES")
else:
    print("NO")

