import java.io.*;
import java.util.*;
import java.math.*;
public class Main
{
    public static void main (String args[]) throws Exception
    {
        BufferedReader stdin = 
            new BufferedReader(
                new InputStreamReader(System.in));

        BigInteger a = new BigInteger("0");
        do
        {
          String line = stdin.readLine();
          StringTokenizer st = new StringTokenizer(line);
          BigInteger b = new BigInteger(st.nextToken());
          a = a.add(b);
          if (b.equals(BigInteger.ZERO)) break;       
         } while (true);
        System.out.println(a);
        
    }
}