Tracy is playing bedwars! Unfortunately, she only has 1.69 CPS. She knows the CPS of each of her ~N~ competitors. She also knows that the chances of her winning are ~0.5 \times \frac{M}{N}~, where ~M~ is the number of competitors with a CPS less than or equal to hers. Given this information, can you output the chances of her winning?

Input Specification

The first line will contain a single integer ~N (1 \leq N \leq 10^3)~. The next ~N~ lines will contain a single decimal value ~M (0 < M \leq 24)~ with two decimal places.

Output Specification

Output a single float, the chances of Tracy winning, to two decimal places.

Sample Input 1

5
1.69
1.68
1.70
1.60
24.02

Sample Output 1

0.30

Sample Input 2

6
1.70
24.04
1.88
12.03
10.02
18.58

Sample Output 2

0.00