import java.util.Scanner;
public class Main {
	public static void main(String args[]){//double 处理果盘
		Scanner in = new Scanner(System.in);
		int n = in.nextInt(),j;
		if (n % 2 == 0){
			j = n/2;
		}else{
			j = 1 + (n -1 )/2;
		}
		float x = (float)j/n;
		System.out.println(x);
		
	}
}
/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