import 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();
	Arrays.sort(v);
	double newIs = (v[0] + v[1]) / 2;
	for (int i=2; i<n; i++) {
	    newIs = (newIs + v[i]) / 2;
	}
	System.out.print(newIs);
    }
} import java.util.*; util.* java 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();
	Arrays.sort(v);
	double newIs = (v[0] + v[1]) / 2;
	for (int i=2; i<n; i++) {
	    newIs = (newIs + v[i]) / 2;
	}
	System.out.print(newIs);
    }
} 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();
	Arrays.sort(v);
	double newIs = (v[0] + v[1]) / 2;
	for (int i=2; i<n; i++) {
	    newIs = (newIs + v[i]) / 2;
	}
	System.out.print(newIs);
    } 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();
	Arrays.sort(v);
	double newIs = (v[0] + v[1]) / 2;
	for (int i=2; i<n; i++) {
	    newIs = (newIs + v[i]) / 2;
	}
	System.out.print(newIs);
    } 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] v i sc.nextDouble() sc.nextDouble sc Arrays.sort(v) Arrays.sort Arrays v double newIs = (v[0] + v[1]) / 2; newIs (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++) {
	    newIs = (newIs + v[i]) / 2;
	} int i=2; int i=2; i 2 i<n i n i++ i++ i {
	    newIs = (newIs + v[i]) / 2;
	} {
	    newIs = (newIs + v[i]) / 2;
	} newIs = (newIs + v[i]) / 2 newIs (newIs + v[i]) / 2 (newIs + v[i]) newIs v[i] v i 2 System.out.print(newIs) System.out.print System.out System System.out newIs 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();
	Arrays.sort(v);
	double newIs = (v[0] + v[1]) / 2;
	for (int i=2; i<n; i++) {
	    newIs = (newIs + v[i]) / 2;
	}
	System.out.print(newIs);
    }
} 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();
	Arrays.sort(v);
	double newIs = (v[0] + v[1]) / 2;
	for (int i=2; i<n; i++) {
	    newIs = (newIs + v[i]) / 2;
	}
	System.out.print(newIs);
    }
} Main
import 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();
	Arrays.sort(v);
	double newIs = (v[0] + v[1]) / 2;
	for (int i=2; i<n; i++) {
	    newIs = (newIs + v[i]) / 2;
	}
	System.out.print(newIs);
    }
}
