import java.util.Scanner;

public class Test {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int[] p = {2,3,5,7,11,13};
		int[] q = {4,6,8,9,10,12};
		int n = sc.nextInt(), cnt = 0;
		for(int i = 0; i < 6; i++){
			for(int j = 0; j < 6; j++){
				if(p[i]*q[j] == n){
					cnt++;
				}
			}
		}
		cnt *= 10;
		System.out.print("0.");
		for(int i = 0; i < 15; i++){
			System.out.print(cnt/36);
			cnt %= 36;
			cnt *= 10;
		}
	}
}