import java.io.BufferedReader;
import java.io.*;
import java.util.*;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Collections;
public class Main {
	public static void main(final String[] args){
    
    Scanner sc = new Scanner(System.in);
    
    int a = sc.nextInt();
    int b = 0;
    if(a % 2 == 0){
        b = a/2;
    }else{
        b = a/2 + 1;
    }

    System.out.println((double)b/a);


    
    


    


    
    


    
	}
}
/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