import java.util.*;
public class Main {
    
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int n = sc.nextInt();
        
        String pattern = "142857";
        String result = "0";
        
        if(n > 0) {
            result += "." + repeat(pattern, n/6);
            result += pattern.substring(0, n%6);
        }
        
        System.out.println(result);
    }
    
    public static String repeat(String str, int n) {
        String temp = "";
        for(int i=0;i<n;i++) {
            temp += str;
        }
        return temp;
    }
    
}