The Robust Spread

Fairhaven Health records how long each patient waited in clinic, and every week throws up a handful of extreme waits that would wreck any spread figure built on averages. The clinic therefore reports the median absolute deviation: the middle value of how far each wait sits from the middle wait. Distance is counted without regard to direction, so a wait ten minutes under the middle and one ten minutes over count as the same distance.

Task: Print the median absolute deviation of the waits.

Input

The first line holds one integer n, how many waits follow. Each of the next n lines holds one wait as a plain number. Waits arrive unsorted, and they may repeat.

Output

One line holding the median absolute deviation with exactly one digit after the decimal point.

Example:

Input:
5
1
2
3
4
100

Output:
1.0