import java.util.*;
public class Main {
  public static void main(String[] args){
    Scanner sc = new Scanner(System.in);
    
   	int n = sc.nextInt();
    
    int oddCount;
    if (n % 2 == 0) {
      oddCount = n / 2;
    } else {
      oddCount = n / 2 + 1;
    }
    
    double oddCountDouble = (double) oddCount;
    double answer = oddCountDouble / n;
    System.out.println(answer);
  }
}
/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