using System; using System.Collections.Generic; using System.Linq; namespace No407_2{ public class Program{ public static void Main(string[] args){ var sr = new StreamReader(); //--------------------------------- var N = sr.Next(); var L = sr.Next(); if(L == 1){ Console.WriteLine(0); return; } Console.WriteLine(Prime.Sieve((int)L - 1).Sum(p => Math.Max(L - p * (N - 1) + 1, 0))); //--------------------------------- } } public class Prime{ public static bool Is(int n){ var sqrt = (int)Math.Sqrt(n); if(n != 2 && n % 2 == 0){ return false; } for(var i = 3; i <= sqrt; i += 2){ if(n % i == 0){ return false; } } return true; } public static IEnumerable Sieve(int n){ var size = (n + 1) >> 1; var sieve = new bool[size]; var sqrt = (int)Math.Sqrt(n); if(n >= 2){ yield return 2; } for(var i = 1; i < sqrt; i++){ if(!sieve[i]){ var d = (i << 1) + 1; yield return d; for(var j = i + d; j < size; j += d){ sieve[j] = true; } } } for(var i = sqrt; i < size; i++){ if(!sieve[i]){ yield return (i << 1) + 1; } } } } public class StreamReader{ private readonly char[] _c = {' '}; private int _index = -1; private string[] _input = new string[0]; public T Next(){ if(_index == _input.Length - 1){ _index = -1; while(true){ string rl = Console.ReadLine(); if(rl == null){ if(typeof(T).IsClass) return default(T); return (T)typeof(T).GetField("MinValue").GetValue(null); } if(rl != ""){ _input = rl.Split(_c, StringSplitOptions.RemoveEmptyEntries); break; } } } return (T)Convert.ChangeType(_input[++_index], typeof(T), System.Globalization.CultureInfo.InvariantCulture); } public T[] Next(int x){ var ret = new T[x]; for(var i = 0; i < x; ++i) ret[i] = Next(); return ret; } public T[][] Next(int y, int x){ var ret = new T[y][]; for(var i = 0; i < y; ++i) ret[i] = Next(x); return ret; } } }