Description:
None
Input Format:
The first line contains a single integer n (1 ≤ n ≤ 1000) — the number of points on a plane.
Each of the next n lines contains two real coordinates xi and yi of the $${ i } ^ { \mathrm { t h } }$$ point, specified with exactly 2 fractional digits. All coordinates are between - 1000 and 1000, inclusive.
Output Format:
Output a single real number θ — the answer to the problem statement. The absolute or relative error of your answer should be at most 10 - 2.
Note:
None