import java.util.*;

public class Main{
	public static void main (String[] args){
		Scanner sc = new Scanner(System.in);
		int counter=0;
		int N= sc.nextInt();
		int f = 0;
		int count = 0;
		for(int i = 1; i <= N; i++){
			f = i%2;
			if(f == 1){
				counter+=1;
			}
		}
		System.out.println((double)counter/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