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.
# Complete the twoStrings function below.
def twoStrings(s1, s2):
    a=Counter(s1)
    flag=False
    for c in s2:
        if c in a.keys():
            flag=True
            break
    if flag:
        return 'YES'
    else:
        return 'NO'

	    	 				  		 						 			 		