How to make a cake you'll never eat.

Ingredients. 

  * 2 carrots
  * 0 calories
  * 100 g chocolate spread
  * 1 pack of flour
  * 1 egg



Method. 

  1. Put calories into the mixing bowl.
  2. Take carrots from refrigerator.
  3. Chop carrots.
  4. Take chocolate spread from refrigerator.
  5. Put chocolate spread into the mixing bowl.
  6. Combine pack of flour into the mixing bowl.
  7. Fold chocolate spread into the mixing bowl.
  8. Add chocolate spread into the mixing bowl.
  9. Put pack of flour into the mixing bowl.
  10. Add egg into the mixing bowl.
  11. Fold pack of flour into the mixing bowl.
  12. Chop carrots until choped.
  13. Pour contents of the mixing bowl into the baking dish.



Serves 1.

Input

The only line of input contains a sequence of integers a0, a1, ... (1 ≤ a0 ≤ 100, 0 ≤ ai ≤ 1000 for i ≥ 1).

Output

Output a single integer.

Examples

Input

4 1 2 3 4


Output

30

import java.io.*;
import java.math.*;
import static java.lang.Math.*;
import java.security.SecureRandom;
import static java.util.Arrays.*;
import java.util.*;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import sun.misc.Regexp;
import java.awt.geom.*;
import sun.net.www.content.text.plain;

public class Main {

    public static void main(String[] args) throws IOException {
        new Main().run();
    }
    StreamTokenizer in;
    PrintWriter out;
//deb////////////////////////////////////////////////

    public static void deb(String n, Object n1) {
        System.out.println(n + " is : " + n1);
    }

    public static void deb(int[] A) {

        for (Object oo : A) {
            System.out.print(oo + " ");
        }
        System.out.println("");
    }

    public static void deb(long[] A) {

        for (Object oo : A) {
            System.out.print(oo + " ");
        }
        System.out.println("");
    }

    public static void deb(boolean[] A) {

        for (Object oo : A) {
            System.out.print(oo + " ");
        }
        System.out.println("");
    }

    public static void deb(double[] A) {

        for (Object oo : A) {
            System.out.print(oo + " ");
        }
        System.out.println("");
    }

    public static void deb(String[] A) {

        for (Object oo : A) {
            System.out.print(oo + " ");
        }
        System.out.println("");
    }

    public static void deb(int[][] A) {
        for (int i = 0; i < A.length; i++) {
            for (Object oo : A[i]) {
                System.out.print(oo + " ");
            }
            System.out.println("");
        }

    }

    public static void deb(double[][] A) {
        for (int i = 0; i < A.length; i++) {
            for (Object oo : A[i]) {
                System.out.print(oo + " ");
            }
            System.out.println("");
        }

    }

    public static void deb(long[][] A) {
        for (int i = 0; i < A.length; i++) {
            for (Object oo : A[i]) {
                System.out.print(oo + " ");
            }
            System.out.println("");
        }

    }

    public static void deb(String[][] A) {
        for (int i = 0; i < A.length; i++) {
            for (Object oo : A[i]) {
                System.out.print(oo + " ");
            }
            System.out.println("");
        }

    }
    /////////////////////////////////////////////////////////////

    int nextInt() throws IOException {
        in.nextToken();
        return (int) in.nval;
    }

    long nextLong() throws IOException {
        in.nextToken();
        return (long) in.nval;
    }

    void run() throws IOException {
//          in = new StreamTokenizer(new BufferedReader(new FileReader("input.txt")));
        // out = new PrintWriter(new FileWriter("output.txt"));
        in = new StreamTokenizer(new BufferedReader(new InputStreamReader(System.in)));
        out = new PrintWriter(new OutputStreamWriter(System.out));
        solve();
        out.flush();
    }
//boolean inR(int x,int y){
//return (x<=0)&&(x<4)&&(y<=0)&&(y<4);
//}

    @SuppressWarnings("unchecked")
    void solve() throws IOException {
        //   BufferedReader re= new BufferedReader(new FileReader("C:\\Users\\ASELA\\Desktop\\PROBLEMSET\\input\\F\\10.in"));
        //   BufferedReader re = new BufferedReader(new InputStreamReader(System.in));
        //   Scanner sc = new Scanner(System.in);
      int N=nextInt();
      int ans=0;
        for (int i = 1; i <= N; i++) {
            ans+=i*nextInt();
        }
        System.out.println(ans);
    }
}
