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];
		double[] val = new double[N];
		double ave = 0;
		for(int i=0;i<N;i++){
			v[i] = sc.nextDouble();
		}
		Arrays.sort(v);
		ave = (v[0] + v[1])/2;
		if(N > 2){
			for(int i = 1; i < N-1; i++){
				ave = (ave + v[i+1])/2;
			}
		}
		System.out.println(ave);
	}
} 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];
		double[] val = new double[N];
		double ave = 0;
		for(int i=0;i<N;i++){
			v[i] = sc.nextDouble();
		}
		Arrays.sort(v);
		ave = (v[0] + v[1])/2;
		if(N > 2){
			for(int i = 1; i < N-1; i++){
				ave = (ave + v[i+1])/2;
			}
		}
		System.out.println(ave);
	}
} Main public static void main(String[] args){
		
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		double[] v = new double[N];
		double[] val = new double[N];
		double ave = 0;
		for(int i=0;i<N;i++){
			v[i] = sc.nextDouble();
		}
		Arrays.sort(v);
		ave = (v[0] + v[1])/2;
		if(N > 2){
			for(int i = 1; i < N-1; i++){
				ave = (ave + v[i+1])/2;
			}
		}
		System.out.println(ave);
	} main {
		
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		double[] v = new double[N];
		double[] val = new double[N];
		double ave = 0;
		for(int i=0;i<N;i++){
			v[i] = sc.nextDouble();
		}
		Arrays.sort(v);
		ave = (v[0] + v[1])/2;
		if(N > 2){
			for(int i = 1; i < N-1; i++){
				ave = (ave + v[i+1])/2;
			}
		}
		System.out.println(ave);
	} 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 double[] val = new double[N]; val new double[N] N double ave = 0; ave 0 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 Arrays.sort(v) Arrays.sort Arrays v ave = (v[0] + v[1])/2 ave (v[0] + v[1])/2 (v[0] + v[1]) v[0] v 0 v[1] v 1 2 if(N > 2){
			for(int i = 1; i < N-1; i++){
				ave = (ave + v[i+1])/2;
			}
		} N > 2 N 2 {
			for(int i = 1; i < N-1; i++){
				ave = (ave + v[i+1])/2;
			}
		} for(int i = 1; i < N-1; i++){
				ave = (ave + v[i+1])/2;
			} int i = 1; int i = 1; i 1 i < N-1 i N-1 N 1 i++ i++ i {
				ave = (ave + v[i+1])/2;
			} {
				ave = (ave + v[i+1])/2;
			} ave = (ave + v[i+1])/2 ave (ave + v[i+1])/2 (ave + v[i+1]) ave v[i+1] v i+1 i 1 2 System.out.println(ave) System.out.println System.out System System.out ave 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];
		double[] val = new double[N];
		double ave = 0;
		for(int i=0;i<N;i++){
			v[i] = sc.nextDouble();
		}
		Arrays.sort(v);
		ave = (v[0] + v[1])/2;
		if(N > 2){
			for(int i = 1; i < N-1; i++){
				ave = (ave + v[i+1])/2;
			}
		}
		System.out.println(ave);
	}
} public class Main{
	public static void main(String[] args){
		
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		double[] v = new double[N];
		double[] val = new double[N];
		double ave = 0;
		for(int i=0;i<N;i++){
			v[i] = sc.nextDouble();
		}
		Arrays.sort(v);
		ave = (v[0] + v[1])/2;
		if(N > 2){
			for(int i = 1; i < N-1; i++){
				ave = (ave + v[i+1])/2;
			}
		}
		System.out.println(ave);
	}
} 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];
		double[] val = new double[N];
		double ave = 0;
		for(int i=0;i<N;i++){
			v[i] = sc.nextDouble();
		}
		Arrays.sort(v);
		ave = (v[0] + v[1])/2;
		if(N > 2){
			for(int i = 1; i < N-1; i++){
				ave = (ave + v[i+1])/2;
			}
		}
		System.out.println(ave);
	}
}