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()
ans = "NO"
if len(s)<4:
    ans = "NO"
else:
    for i in range(0, len(s)):
        if i+1<len(s) and s[i]+s[i+1]=="AB":
            for j in range(i+2,len(s)):
                if j+1<len(s) and s[j]+s[j+1]=="BA":
                    ans = "YES"
    for i in range(0, len(s)):
        if i+1<len(s) and s[i]+s[i+1]=="BA":
            for j in range(i+2,len(s)):
                if j+1<len(s) and s[j]+s[j+1]=="AB":
                    ans = "YES"
                    
                    
print(ans)
    