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 catch(s):
    foundA = False
    foundB = False
    reset = 0
    for i in range(0, len(s)-1):
        if reset:
            reset -= 1
            continue
        if s[i:i+2] == "AB":
            foundA = True
            reset = 2
        elif s[i:i+2] == "BA": 
            foundB = True
            reset = 2
        if foundA and foundB:
            print("YES")
            break
    else:
        print("NO")

s = input()
catch(s)
