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.IOException;
import java.util.InputMismatchException;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.io.Writer;
import java.math.BigInteger;
import java.io.InputStream;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 * @author Egor Kulikov (egor@egork.net)
 */
public class Main {
	public static void main(String[] args) {
		InputStream inputStream = System.in;
		OutputStream outputStream = System.out;
		InputReader in = new InputReader(inputStream);
		OutputWriter out = new OutputWriter(outputStream);
		TaskC solver = new TaskC();
		solver.solve(1, in, out);
		out.close();
	}
}

class TaskC {
	public void solve(int testNumber, InputReader in, OutputWriter out) {
		int count = in.readInt();
		int[] array = IOUtils.readIntArray(in, count);
		int answer = 0;
		for (int i = 0; i < count; i++)
			answer += (i + 1) * array[i];
		out.printLine(answer);
	}
}

class InputReader {

	private InputStream stream;
	private byte[] buf = new byte[1024];
	private int curChar;
	private int numChars;

	public InputReader(InputStream stream) {
		this.stream = stream;
	}

	public int read() {
		if (numChars == -1)
			throw new InputMismatchException();
		if (curChar >= numChars) {
			curChar = 0;
			try {
				numChars = stream.read(buf);
			} catch (IOException e) {
				throw new InputMismatchException();
			}
			if (numChars <= 0)
				return -1;
		}
		return buf[curChar++];
	}

	public int readInt() {
		int c = read();
		while (isSpaceChar(c))
			c = read();
		int sgn = 1;
		if (c == '-') {
			sgn = -1;
			c = read();
		}
		int res = 0;
		do {
			if (c < '0' || c > '9')
				throw new InputMismatchException();
			res *= 10;
			res += c - '0';
			c = read();
		} while (!isSpaceChar(c));
		return res * sgn;
	}

	public static boolean isSpaceChar(int c) {
		return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
	}

	}

class OutputWriter {
	private final PrintWriter writer;

	public OutputWriter(OutputStream outputStream) {
		writer = new PrintWriter(outputStream);
	}

	public OutputWriter(Writer writer) {
		this.writer = new PrintWriter(writer);
	}

	public void print(Object...objects) {
		for (int i = 0; i < objects.length; i++) {
			if (i != 0)
				writer.print(' ');
			writer.print(objects[i]);
		}
	}

	public void printLine(Object...objects) {
		print(objects);
		writer.println();
	}

	public void close() {
		writer.close();
	}

	}

class IOUtils {

	public static int[] readIntArray(InputReader in, int size) {
		int[] array = new int[size];
		for (int i = 0; i < size; i++)
			array[i] = in.readInt();
		return array;
	}

	}

