import java.util.*;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		// 整数の入力
		int N = sc.nextInt();
		
		double[] V = new double[N];
  		
		double ave = 0;
		int max = 0;
	    int max2 = 0;
		for(int i = 0 ;i<N;i++){
			V[i] = sc.nextInt();
        }
      
      	Arrays.sort(V);
      
      	for(int i = 1 ;i<N;i++){
			if(ave == 0){
              ave = (V[0] + V[1]) / 2;
            }else{
              ave = (ave + V[i]) /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);
		// 整数の入力
		int N = sc.nextInt();
		
		double[] V = new double[N];
  		
		double ave = 0;
		int max = 0;
	    int max2 = 0;
		for(int i = 0 ;i<N;i++){
			V[i] = sc.nextInt();
        }
      
      	Arrays.sort(V);
      
      	for(int i = 1 ;i<N;i++){
			if(ave == 0){
              ave = (V[0] + V[1]) / 2;
            }else{
              ave = (ave + V[i]) /2;
            }
        }
 	  
      
		System.out.println(ave);
	}
} Main public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		// 整数の入力
		int N = sc.nextInt();
		
		double[] V = new double[N];
  		
		double ave = 0;
		int max = 0;
	    int max2 = 0;
		for(int i = 0 ;i<N;i++){
			V[i] = sc.nextInt();
        }
      
      	Arrays.sort(V);
      
      	for(int i = 1 ;i<N;i++){
			if(ave == 0){
              ave = (V[0] + V[1]) / 2;
            }else{
              ave = (ave + V[i]) /2;
            }
        }
 	  
      
		System.out.println(ave);
	} main {
		Scanner sc = new Scanner(System.in);
		// 整数の入力
		int N = sc.nextInt();
		
		double[] V = new double[N];
  		
		double ave = 0;
		int max = 0;
	    int max2 = 0;
		for(int i = 0 ;i<N;i++){
			V[i] = sc.nextInt();
        }
      
      	Arrays.sort(V);
      
      	for(int i = 1 ;i<N;i++){
			if(ave == 0){
              ave = (V[0] + V[1]) / 2;
            }else{
              ave = (ave + V[i]) /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 ave = 0; ave 0 int max = 0; max 0 int max2 = 0; max2 0 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 for(int i = 1 ;i<N;i++){
			if(ave == 0){
              ave = (V[0] + V[1]) / 2;
            }else{
              ave = (ave + V[i]) /2;
            }
        } int i = 1 ; int i = 1 ; i 1 i<N i N i++ i++ i {
			if(ave == 0){
              ave = (V[0] + V[1]) / 2;
            }else{
              ave = (ave + V[i]) /2;
            }
        } {
			if(ave == 0){
              ave = (V[0] + V[1]) / 2;
            }else{
              ave = (ave + V[i]) /2;
            }
        } if(ave == 0){
              ave = (V[0] + V[1]) / 2;
            }else{
              ave = (ave + V[i]) /2;
            } ave == 0 ave 0 {
              ave = (V[0] + V[1]) / 2;
            } 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 {
              ave = (ave + V[i]) /2;
            } ave = (ave + V[i]) /2 ave (ave + V[i]) /2 (ave + V[i]) ave V[i] V i 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);
		// 整数の入力
		int N = sc.nextInt();
		
		double[] V = new double[N];
  		
		double ave = 0;
		int max = 0;
	    int max2 = 0;
		for(int i = 0 ;i<N;i++){
			V[i] = sc.nextInt();
        }
      
      	Arrays.sort(V);
      
      	for(int i = 1 ;i<N;i++){
			if(ave == 0){
              ave = (V[0] + V[1]) / 2;
            }else{
              ave = (ave + V[i]) /2;
            }
        }
 	  
      
		System.out.println(ave);
	}
} public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		// 整数の入力
		int N = sc.nextInt();
		
		double[] V = new double[N];
  		
		double ave = 0;
		int max = 0;
	    int max2 = 0;
		for(int i = 0 ;i<N;i++){
			V[i] = sc.nextInt();
        }
      
      	Arrays.sort(V);
      
      	for(int i = 1 ;i<N;i++){
			if(ave == 0){
              ave = (V[0] + V[1]) / 2;
            }else{
              ave = (ave + V[i]) /2;
            }
        }
 	  
      
		System.out.println(ave);
	}
} Main
import java.util.*;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		// 整数の入力
		int N = sc.nextInt();
		
		double[] V = new double[N];
  		
		double ave = 0;
		int max = 0;
	    int max2 = 0;
		for(int i = 0 ;i<N;i++){
			V[i] = sc.nextInt();
        }
      
      	Arrays.sort(V);
      
      	for(int i = 1 ;i<N;i++){
			if(ave == 0){
              ave = (V[0] + V[1]) / 2;
            }else{
              ave = (ave + V[i]) /2;
            }
        }
 	  
      
		System.out.println(ave);
	}
}