import java.util.*;
class test{
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		int K = sc.nextInt();
		int PrimeNumbers[] = {2,3,5,7,11,13}; 
		int SynthesisNumbers[] = {2,4,6,8,10,12};
		int count = 0;
		
		for(int i=0; i<PrimeNumbers.length; i++){
			for(int j=0; j<SynthesisNumbers.length; j++){
				if(PrimeNumbers[i] * SynthesisNumbers[j] == K){
					count++;
				}
			}
		}

		System.out.println(String.format("%.12f", (double)count/36));
		
	}
}