import std.algorithm;
import std.array;
import std.conv;
import std.math;
import std.range;
import std.stdio;
import std.string;
import std.typecons;

int readint() {
    return readln.chomp.to!int;
}

int[] readints() {
    return readln.split.map!(to!int).array;
}

void main() {
    int k = readint();

    int n = 0;
    foreach (a; [2, 3, 5, 7, 11, 13]) {
        foreach (b; [4, 6, 8, 9, 10, 12]) {
            if (a * b == k) {
                n++;
            }
        }
    }

    writefln("%.12f", n / 36.0);
}