Description

Lee once saw a way to calculate secret number, and he's curious about how he can mutate the problem, so he came up with an idea, calculate the secret number's secret factor.

Lee's Secret Primary Factor's calculating steps are:

Given a interger input ~N~

1. combine ~N~'s odd and even digits into 2 numbers
2. subtract 2 numbers and take it's absolute
3. calculate the largest primary factor
4. the result is what Lee wanted

For example:

~N = 48422~

Odd	Even
~442~	~82~

~|Odd-Even| = 360 = 2 \times 2 \times 2 \times 3 \times 3 \times 5 = 2^3 \times 3^2 \times 5~

Therefore, the Secret Primary Factor of ~58422~ is ~5~

Constraints

The digit count of input (~N~):

~2 \le len(input) \le 144~

The digit count of output:

~1 \le len(output) \le 2~

Sample IO