import java.util.*;
import java.lang.*;
import java.io.*;

// The main method must be in a class named "Main".
class Main {
    public static Boolean prime(int val)
    {
        for(int i=2;i<val;i++)
        {
            if(val%i==0) return false;
        }
        return true;
    }
    public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);
        int input=sc.nextInt();
        int input2=sc.nextInt();
        int[] array=new int[input];
        for(int i=0;i<input;i++)
            {
                array[i]=sc.nextInt();
            }
        int result=0;
        for(int i=1;i<input;i++)
        {
            if(prime(i+1))
            {
                //System.out.println(i);
                result=result+Math.min(array[i],input2);
            }
        }
        
        System.out.println(result);
    }
}