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.
def check(x):
    a = 0
    b = 0
    for i in range(len(x)-1):
        if x[i]== "A" and x[i+1] == "B":
            a = a+1
        if  x[i] == "B" and x[i+1] =="A":
            b = b+1
    if a != 0 and b != 0:
        return "YES"
    else:
        return "NO"

x = input()

print(check(x))