import java.util.Scanner;//入力を取得する(Scanner)

class Main {
        public static void main(String arts[]) {
											 int N;
											 Scanner sc = new Scanner(System.in);
											 N = sc.nextInt();

											 int target;
											 target = (N+1) / 2;// kiriage
											 double n = N;

											 System.out.println(target / n );
               }
		}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz