import java.io.*;

public class No211{
    public static void main(String[] args) throws IOException{
        String str = new BufferedReader(new InputStreamReader(System.in)).readLine();
        int k = Integer.parseInt(str);
        int[] pnd = {2,3,5,7,11,13};
        int[] cnd = {4,6,8,9,10,12};
        int count  = 0;
        for(int i=0; i < 6; i++){
            for(int j=0; j < 6; j++){
                if(pnd[i] * cnd[j] == k){
                    count++;
                    break;
                }
            }
        }
        if(count == 0) System.out.println(0);
        else System.out.println((double)count/36);
    }
}