using System; using System.Collections.Generic; using System.Linq; namespace yukicoder { public class Program { public static void Main() { var line = Console.ReadLine().Split(' '); var n = int.Parse(line[0]); var p = double.Parse(line[1]); double sum = 0; for (var i = 2; i <= n; i++) { sum += Math.Pow((1 - p), DivisorCount(i)); } Console.WriteLine(sum); } public static int DivisorCount(int n) { var m = 0; var k = Math.Sqrt(n); for (var i = 2; i <= k; i++) { if (n % i == 0) { m++; if (i != k) { m++; } } } return m; } } }