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()
x=0;y=0;i=0;n=len(s)-1
cx=0;cy=0
while(i<n):
    if s[i]=='A' and s[i+1]=='B':
        x+=1;cx=i;i+=1
    elif s[i]=='B' and s[i+1]=='A':
        y+=1;cy=i;i+=1
    if(x+y==2): 
        break
    i+=1
print("YES" if x+y>2 or (x+y==2 and min(cx,cy)+1!=max(cx,cy)) else "NO")