import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.Scanner;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author ky112233
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        CAlchemist solver = new CAlchemist();
        solver.solve(1, in, out);
        out.close();
    }

    static class CAlchemist {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            int n = in.nextInt();
            double[] v = new double[n];
            for (int i = 0; i < n; i++) v[i] = in.nextDouble();
            Arrays.sort(v);
            double sum = (v[0] + v[1]) / 2;
            for (int i = 2; i < n; i++) {
                sum = (sum + v[i]) / 2;
            }
            out.println(sum);
        }

    }
}
 import java.io.OutputStream; OutputStream java.io import java.io.IOException; IOException java.io import java.io.InputStream; InputStream java.io import java.io.PrintWriter; PrintWriter java.io import java.util.Arrays; Arrays java.util import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        CAlchemist solver = new CAlchemist();
        solver.solve(1, in, out);
        out.close();
    }

    static class CAlchemist {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            int n = in.nextInt();
            double[] v = new double[n];
            for (int i = 0; i < n; i++) v[i] = in.nextDouble();
            Arrays.sort(v);
            double sum = (v[0] + v[1]) / 2;
            for (int i = 2; i < n; i++) {
                sum = (sum + v[i]) / 2;
            }
            out.println(sum);
        }

    }
} Main public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        CAlchemist solver = new CAlchemist();
        solver.solve(1, in, out);
        out.close();
    } main {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        CAlchemist solver = new CAlchemist();
        solver.solve(1, in, out);
        out.close();
    } InputStream inputStream = System.in; inputStream System.in System System.in OutputStream outputStream = System.out; outputStream System.out System System.out Scanner in = new Scanner(inputStream); in new Scanner(inputStream) PrintWriter out = new PrintWriter(outputStream); out new PrintWriter(outputStream) CAlchemist solver = new CAlchemist(); solver new CAlchemist() solver.solve(1, in, out) solver.solve solver 1 in out out.close() out.close out String[] args args static class CAlchemist {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            int n = in.nextInt();
            double[] v = new double[n];
            for (int i = 0; i < n; i++) v[i] = in.nextDouble();
            Arrays.sort(v);
            double sum = (v[0] + v[1]) / 2;
            for (int i = 2; i < n; i++) {
                sum = (sum + v[i]) / 2;
            }
            out.println(sum);
        }

    } CAlchemist public void solve(int testNumber, Scanner in, PrintWriter out) {
            int n = in.nextInt();
            double[] v = new double[n];
            for (int i = 0; i < n; i++) v[i] = in.nextDouble();
            Arrays.sort(v);
            double sum = (v[0] + v[1]) / 2;
            for (int i = 2; i < n; i++) {
                sum = (sum + v[i]) / 2;
            }
            out.println(sum);
        } solve {
            int n = in.nextInt();
            double[] v = new double[n];
            for (int i = 0; i < n; i++) v[i] = in.nextDouble();
            Arrays.sort(v);
            double sum = (v[0] + v[1]) / 2;
            for (int i = 2; i < n; i++) {
                sum = (sum + v[i]) / 2;
            }
            out.println(sum);
        } int n = in.nextInt(); n in.nextInt() in.nextInt in double[] v = new double[n]; v new double[n] n for (int i = 0; i < n; i++) v[i] = in.nextDouble(); int i = 0; int i = 0; i 0 i < n i n i++ i++ i v[i] = in.nextDouble(); v[i] = in.nextDouble() v[i] v i in.nextDouble() in.nextDouble in Arrays.sort(v) Arrays.sort Arrays v double sum = (v[0] + v[1]) / 2; sum (v[0] + v[1]) / 2 (v[0] + v[1]) v[0] v 0 v[1] v 1 2 for (int i = 2; i < n; i++) {
                sum = (sum + v[i]) / 2;
            } int i = 2; int i = 2; i 2 i < n i n i++ i++ i {
                sum = (sum + v[i]) / 2;
            } {
                sum = (sum + v[i]) / 2;
            } sum = (sum + v[i]) / 2 sum (sum + v[i]) / 2 (sum + v[i]) sum v[i] v i 2 out.println(sum) out.println out sum int testNumber testNumber Scanner in in PrintWriter out out public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        CAlchemist solver = new CAlchemist();
        solver.solve(1, in, out);
        out.close();
    }

    static class CAlchemist {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            int n = in.nextInt();
            double[] v = new double[n];
            for (int i = 0; i < n; i++) v[i] = in.nextDouble();
            Arrays.sort(v);
            double sum = (v[0] + v[1]) / 2;
            for (int i = 2; i < n; i++) {
                sum = (sum + v[i]) / 2;
            }
            out.println(sum);
        }

    }
} public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        CAlchemist solver = new CAlchemist();
        solver.solve(1, in, out);
        out.close();
    }

    static class CAlchemist {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            int n = in.nextInt();
            double[] v = new double[n];
            for (int i = 0; i < n; i++) v[i] = in.nextDouble();
            Arrays.sort(v);
            double sum = (v[0] + v[1]) / 2;
            for (int i = 2; i < n; i++) {
                sum = (sum + v[i]) / 2;
            }
            out.println(sum);
        }

    }
} Main
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.Scanner;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author ky112233
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        CAlchemist solver = new CAlchemist();
        solver.solve(1, in, out);
        out.close();
    }

    static class CAlchemist {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            int n = in.nextInt();
            double[] v = new double[n];
            for (int i = 0; i < n; i++) v[i] = in.nextDouble();
            Arrays.sort(v);
            double sum = (v[0] + v[1]) / 2;
            for (int i = 2; i < n; i++) {
                sum = (sum + v[i]) / 2;
            }
            out.println(sum);
        }

    }
}

