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.
import sys

string = sys.stdin.readline()
a = string.find("AB", 0)
b = string.find("BA", a + 2)
c = string.find("BA", 0)
d = string.find("AB", a + 2)

result = (a+b > max(a, b) or c+d > max(c, d))

if result:
    output = "YES"
else:
    output = "NO"
print(output)
