def f(n):
 B=bin(n)[2:]
 L=len(B)
 M=L//2
 if B=='1'*L:return True
 S=str(int(B[:M])+int(B[:-M-1:-1]))
 if(~L%2==0 and'0'==B[M]) or'2'in S:return False
 if S=='1'*len(S):return True
 return f(int(S,2))