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 re, sys

string = str(sys.stdin.readline())
a = "AB.*BA|BA.*AB"
if re.match(a, string):
    print("YES")
    exit(0)
print("NO")
