import java.util.*;
import java.io.*;
import java.awt.Point;
import java.util.regex.*;
import java.math.*;
import java.text.*;

public class _2 {

    static boolean[] sieve = new boolean[100002];

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) throws IOException {
        Scanner fin = new Scanner(new FileReader("DATA2.txt"));
        PrintWriter fout = new PrintWriter(new FileWriter("OUT2.txt"));

        for(int i=2;i<100002;i++) {
            if(!sieve[i]) {
                for(int x=2;x*i<100002;x++) {
                    sieve[x*i] = true;
                }
            }
        }

        while(fin.hasNext()) {
            int x = fin.nextInt();
            long lSum = 0;



            for(int i=2;i<=x;i++){
                if(!sieve[i]) {
                    lSum += i;
                }
            }
            fout.println(lSum);
        }

        fout.close();
        fin.close();
    }
}