A 2x2 Grid of Charts

Halewood Reporting is building a dashboard tile for an operations wall. One set of readings is shown four ways at once, in a two-by-two block of panels: bars, a line, a banded shape and a dot per reading. Each panel answers a different question about the same numbers, and a viewer walking past reads whichever one they came for. A single average is printed beneath the block as the tile's headline.

Task: Print the average of the readings.

Input

The first line holds an integer n, the number of readings. Each of the next n lines holds one reading, possibly with decimals. n is at least 1.

Output

One line with exactly 2 digits after the decimal point. An average of twenty-five prints as 25.00.

Example:

Input:
4
10
20
30
40

Output:
25.00