import java.util.*;
import java.util.ArrayDeque;
import java.util.Queue;
import java.math.RoundingMode;
import java.math.BigDecimal;


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.nextInt();
	  }
	  Arrays.sort(v);
	  double sum = (v[0]+v[1])/2; 
	  for(int i = 2; i < n; i++) {
		  sum = (sum+v[i])/2;
	  }
	  System.out.println(sum);
	}
} import java.util.*; util.* java import java.util.ArrayDeque; ArrayDeque java.util import java.util.Queue; Queue java.util import java.math.RoundingMode; RoundingMode java.math import java.math.BigDecimal; BigDecimal java.math 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.nextInt();
	  }
	  Arrays.sort(v);
	  double sum = (v[0]+v[1])/2; 
	  for(int i = 2; i < n; i++) {
		  sum = (sum+v[i])/2;
	  }
	  System.out.println(sum);
	}
} 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.nextInt();
	  }
	  Arrays.sort(v);
	  double sum = (v[0]+v[1])/2; 
	  for(int i = 2; i < n; i++) {
		  sum = (sum+v[i])/2;
	  }
	  System.out.println(sum);
	} 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.nextInt();
	  }
	  Arrays.sort(v);
	  double sum = (v[0]+v[1])/2; 
	  for(int i = 2; i < n; i++) {
		  sum = (sum+v[i])/2;
	  }
	  System.out.println(sum);
	} 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.nextInt();
	  } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
		  v[i] = sc.nextInt();
	  } {
		  v[i] = sc.nextInt();
	  } v[i] = sc.nextInt() v[i] v i sc.nextInt() sc.nextInt sc 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 System.out.println(sum) System.out.println System.out System System.out sum 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.nextInt();
	  }
	  Arrays.sort(v);
	  double sum = (v[0]+v[1])/2; 
	  for(int i = 2; i < n; i++) {
		  sum = (sum+v[i])/2;
	  }
	  System.out.println(sum);
	}
} 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.nextInt();
	  }
	  Arrays.sort(v);
	  double sum = (v[0]+v[1])/2; 
	  for(int i = 2; i < n; i++) {
		  sum = (sum+v[i])/2;
	  }
	  System.out.println(sum);
	}
} Main
import java.util.*;
import java.util.ArrayDeque;
import java.util.Queue;
import java.math.RoundingMode;
import java.math.BigDecimal;


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.nextInt();
	  }
	  Arrays.sort(v);
	  double sum = (v[0]+v[1])/2; 
	  for(int i = 2; i < n; i++) {
		  sum = (sum+v[i])/2;
	  }
	  System.out.println(sum);
	}
}