import java.util.*;

class Main {
  public static void main(String[] args) {
  	Scanner sc = new Scanner(System.in);
    
    int N = Integer.parseInt(sc.next());
    
    int odd = N - (N / 2);
    
    double result = (double) odd / N;
    
    System.out.println(result);
  
  }
}
/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