def zero(x): t = "" for a,b in zip(x[::2],x[1::2]): t += b+a return tdef one(x): t = "" for a,b in zip(x[::2],x[1::2]): t += b+a if b<a else a+b return tdef two(x): t = "" for a,b in zip(x[:len(x)//2],x[len(x)//2:]): t += a+b return t