
public class Main {
    public static void main(String[] args) {

	int cnt = 0;
	double out;
       
	int  n = new java.util.Scanner(System.in).nextInt();


	for(int i = n; i >= 1; i--) {
	    if(i % 2 != 0) {
		cnt++;
	
	    }
	}

	out = (double)cnt / (double)n;
	System.out.printf("%.8f", out);
    }
}
/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