import java.math.BigInteger;

public class prob16 {
  public static void main(String args[]) {
    BigInteger prod = new BigInteger("2");
    int sum = 0;
    prod = prod.pow(1000);
    while (prod.doubleValue() > 0.5) {
      BigInteger m = prod.mod(new BigInteger("" + 10));
      sum += m.intValue();
      prod = prod.divide(new BigInteger("" + 10));
    }
    System.out.println("Sum = " + sum);
  }
}