import java.util.Scanner;
 
public class Main {
 
	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
 
		Scanner scanner = new Scanner(System.in);
 
		//入力表示
		int N = scanner.nextInt();
		int B = 0;
 
		if (N % 2 == 0) {
			B = N / 2;
		
		} else {
			B = N / 2 + 1;
		}
 
	 System.out.println((double)B/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