import java.util.* ; public class InterstellarTravelHigh_tgr { final static double TAU = 2 * Math.PI ; static double circabs(double a) { a %= TAU ; if (a > Math.PI) return TAU - a ; return a ; } static class Inflection implements Comparable { Inflection(double a_, double b_) { a = a_ ; b = b_ ; } public int compareTo(Object o) { Inflection c = (Inflection)o ; if (a < c.a) return -1 ; if (a > c.a) return 1 ; return 0 ; } double a, b ; } static Vector infs = new Vector() ; static void addslope(double where, double val) { infs.add(new Inflection(where, val)) ; } public static void main(String[] args) { Scanner sc = new Scanner(System.in) ; int n = sc.nextInt() ; double curslope = 0 ; double curval = 0 ; for (int i=0; i