import java.util.Arrays;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		double[] v = new double[n];
		for (int i = 0; i < n; i++) {
			v[i] = sc.nextDouble();
		}
		sc.close();

		Arrays.sort(v);

		double vAve = (v[0] + v[1]) / 2;
		double tmp = 0;

		for (int i = 2; i < n; i++) {
			tmp = vAve;
			vAve = (tmp + v[i]) / 2;
		}

		System.out.println(vAve);

	}

} import java.util.Arrays; Arrays java.util import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		double[] v = new double[n];
		for (int i = 0; i < n; i++) {
			v[i] = sc.nextDouble();
		}
		sc.close();

		Arrays.sort(v);

		double vAve = (v[0] + v[1]) / 2;
		double tmp = 0;

		for (int i = 2; i < n; i++) {
			tmp = vAve;
			vAve = (tmp + v[i]) / 2;
		}

		System.out.println(vAve);

	}

} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		double[] v = new double[n];
		for (int i = 0; i < n; i++) {
			v[i] = sc.nextDouble();
		}
		sc.close();

		Arrays.sort(v);

		double vAve = (v[0] + v[1]) / 2;
		double tmp = 0;

		for (int i = 2; i < n; i++) {
			tmp = vAve;
			vAve = (tmp + v[i]) / 2;
		}

		System.out.println(vAve);

	} main {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		double[] v = new double[n];
		for (int i = 0; i < n; i++) {
			v[i] = sc.nextDouble();
		}
		sc.close();

		Arrays.sort(v);

		double vAve = (v[0] + v[1]) / 2;
		double tmp = 0;

		for (int i = 2; i < n; i++) {
			tmp = vAve;
			vAve = (tmp + v[i]) / 2;
		}

		System.out.println(vAve);

	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc double[] v = new double[n]; v new double[n] n for (int i = 0; i < n; i++) {
			v[i] = sc.nextDouble();
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			v[i] = sc.nextDouble();
		} {
			v[i] = sc.nextDouble();
		} v[i] = sc.nextDouble() v[i] v i sc.nextDouble() sc.nextDouble sc sc.close() sc.close sc Arrays.sort(v) Arrays.sort Arrays v double vAve = (v[0] + v[1]) / 2; vAve (v[0] + v[1]) / 2 (v[0] + v[1]) v[0] v 0 v[1] v 1 2 double tmp = 0; tmp 0 for (int i = 2; i < n; i++) {
			tmp = vAve;
			vAve = (tmp + v[i]) / 2;
		} int i = 2; int i = 2; i 2 i < n i n i++ i++ i {
			tmp = vAve;
			vAve = (tmp + v[i]) / 2;
		} {
			tmp = vAve;
			vAve = (tmp + v[i]) / 2;
		} tmp = vAve tmp vAve vAve = (tmp + v[i]) / 2 vAve (tmp + v[i]) / 2 (tmp + v[i]) tmp v[i] v i 2 System.out.println(vAve) System.out.println System.out System System.out vAve String[] args args public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		double[] v = new double[n];
		for (int i = 0; i < n; i++) {
			v[i] = sc.nextDouble();
		}
		sc.close();

		Arrays.sort(v);

		double vAve = (v[0] + v[1]) / 2;
		double tmp = 0;

		for (int i = 2; i < n; i++) {
			tmp = vAve;
			vAve = (tmp + v[i]) / 2;
		}

		System.out.println(vAve);

	}

} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		double[] v = new double[n];
		for (int i = 0; i < n; i++) {
			v[i] = sc.nextDouble();
		}
		sc.close();

		Arrays.sort(v);

		double vAve = (v[0] + v[1]) / 2;
		double tmp = 0;

		for (int i = 2; i < n; i++) {
			tmp = vAve;
			vAve = (tmp + v[i]) / 2;
		}

		System.out.println(vAve);

	}

} Main
import java.util.Arrays;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		double[] v = new double[n];
		for (int i = 0; i < n; i++) {
			v[i] = sc.nextDouble();
		}
		sc.close();

		Arrays.sort(v);

		double vAve = (v[0] + v[1]) / 2;
		double tmp = 0;

		for (int i = 2; i < n; i++) {
			tmp = vAve;
			vAve = (tmp + v[i]) / 2;
		}

		System.out.println(vAve);

	}

}
