import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.math.BigDecimal;

public class No081 {

    public static void main(String[] args) {
        try {
            BufferedReader br = new BufferedReader(new InputStreamReader(
                    System.in));
            int N = Integer.parseInt(br.readLine());

            BigDecimal a = new BigDecimal("0");
            for (int i = 0; i < N; i++) {
                a = a.add(new BigDecimal(br.readLine()));
            }
            System.out.printf("%.10f", a);
        } catch (Exception e) {
            System.err.println("Error:" + e.getMessage());
        }
    }

}