import java.util.*;
public class Main {
  public static void main(String[] args) {
    Scanner scan = new Scanner(System.in);
    int n = scan.nextInt();
    //System.out.println(n);
    int count = 0;
    for (int i = 1;i <= n; i++) {
      if(i%2 == 1) {
       count += 1; 
       //System.out.println(count);
      }else{
       count += 0;  
       //System.out.println("偶数");
      }
    }
    System.out.println((float)count / 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