import java.util.*;
public class Main{


public static void main(String[] args){
Scanner obj=new Scanner(System.in);
int n=obj.nextInt();
float o=0;
float ans=0;
for(int i=1;i<=n;i++){

if(i%2!=0){
o++;
}

}

ans=o/n;
System.out.println(ans);






}




}
/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