import std.algorithm, std.array, std.container, std.range, std.bitmanip;
import std.numeric, std.math, std.bigint, std.random, core.bitop;
import std.string, std.regex, std.conv, std.stdio, std.typecons;

const auto di1 = [2, 3, 5, 7, 11, 13];
const auto di2 = [4, 6, 8, 9, 10, 12];

void main()
{
  auto k = readln.chomp.to!int;
  auto r = 0;
  foreach (d1; di1)
    foreach (d2; di2)
      if (d1 * d2 == k) ++r;
  writefln("%.13f", r.to!real / 36);
}