import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Scanner;
import java.util.function.IntToDoubleFunction;
 
/**
 * @author yoshizaki
 *
 */
public class Main {
    public static void main(String[] args) {
        Scanner scanner= new Scanner(System.in);
        int num = scanner.nextInt();
        List<Double> values = new ArrayList<Double>();
        for (int i = 0 ; i < num ; i++) {
            values.add(scanner.nextDouble());
        }
        Collections.sort(values);
        for(int i = 0; i < num-1 ; i++) {
            Double v = (values.get(i) + values.get(i+1))/2;
            values.set(i+1, v);
        }
        System.out.println( values.get(num-1));
    
    
        
    }
} import java.util.ArrayList; ArrayList java.util import java.util.Collections; Collections java.util import java.util.List; List java.util import java.util.Scanner; Scanner java.util import java.util.function.IntToDoubleFunction; IntToDoubleFunction java.util.function public class Main {
    public static void main(String[] args) {
        Scanner scanner= new Scanner(System.in);
        int num = scanner.nextInt();
        List<Double> values = new ArrayList<Double>();
        for (int i = 0 ; i < num ; i++) {
            values.add(scanner.nextDouble());
        }
        Collections.sort(values);
        for(int i = 0; i < num-1 ; i++) {
            Double v = (values.get(i) + values.get(i+1))/2;
            values.set(i+1, v);
        }
        System.out.println( values.get(num-1));
    
    
        
    }
} Main public static void main(String[] args) {
        Scanner scanner= new Scanner(System.in);
        int num = scanner.nextInt();
        List<Double> values = new ArrayList<Double>();
        for (int i = 0 ; i < num ; i++) {
            values.add(scanner.nextDouble());
        }
        Collections.sort(values);
        for(int i = 0; i < num-1 ; i++) {
            Double v = (values.get(i) + values.get(i+1))/2;
            values.set(i+1, v);
        }
        System.out.println( values.get(num-1));
    
    
        
    } main {
        Scanner scanner= new Scanner(System.in);
        int num = scanner.nextInt();
        List<Double> values = new ArrayList<Double>();
        for (int i = 0 ; i < num ; i++) {
            values.add(scanner.nextDouble());
        }
        Collections.sort(values);
        for(int i = 0; i < num-1 ; i++) {
            Double v = (values.get(i) + values.get(i+1))/2;
            values.set(i+1, v);
        }
        System.out.println( values.get(num-1));
    
    
        
    } Scanner scanner= new Scanner(System.in); scanner new Scanner(System.in) int num = scanner.nextInt(); num scanner.nextInt() scanner.nextInt scanner List<Double> values = new ArrayList<Double>(); values new ArrayList<Double>() for (int i = 0 ; i < num ; i++) {
            values.add(scanner.nextDouble());
        } int i = 0 ; int i = 0 ; i 0 i < num i num i++ i++ i {
            values.add(scanner.nextDouble());
        } {
            values.add(scanner.nextDouble());
        } values.add(scanner.nextDouble()) values.add values scanner.nextDouble() scanner.nextDouble scanner Collections.sort(values) Collections.sort Collections values for(int i = 0; i < num-1 ; i++) {
            Double v = (values.get(i) + values.get(i+1))/2;
            values.set(i+1, v);
        } int i = 0; int i = 0; i 0 i < num-1 i num-1 num 1 i++ i++ i {
            Double v = (values.get(i) + values.get(i+1))/2;
            values.set(i+1, v);
        } {
            Double v = (values.get(i) + values.get(i+1))/2;
            values.set(i+1, v);
        } Double v = (values.get(i) + values.get(i+1))/2; v (values.get(i) + values.get(i+1))/2 (values.get(i) + values.get(i+1)) values.get(i) values.get values i values.get(i+1) values.get values i+1 i 1 2 values.set(i+1, v) values.set values i+1 i 1 v System.out.println( values.get(num-1)) System.out.println System.out System System.out values.get(num-1) values.get values num-1 num 1 String[] args args public class Main {
    public static void main(String[] args) {
        Scanner scanner= new Scanner(System.in);
        int num = scanner.nextInt();
        List<Double> values = new ArrayList<Double>();
        for (int i = 0 ; i < num ; i++) {
            values.add(scanner.nextDouble());
        }
        Collections.sort(values);
        for(int i = 0; i < num-1 ; i++) {
            Double v = (values.get(i) + values.get(i+1))/2;
            values.set(i+1, v);
        }
        System.out.println( values.get(num-1));
    
    
        
    }
} public class Main {
    public static void main(String[] args) {
        Scanner scanner= new Scanner(System.in);
        int num = scanner.nextInt();
        List<Double> values = new ArrayList<Double>();
        for (int i = 0 ; i < num ; i++) {
            values.add(scanner.nextDouble());
        }
        Collections.sort(values);
        for(int i = 0; i < num-1 ; i++) {
            Double v = (values.get(i) + values.get(i+1))/2;
            values.set(i+1, v);
        }
        System.out.println( values.get(num-1));
    
    
        
    }
} Main
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Scanner;
import java.util.function.IntToDoubleFunction;
 
/**
 * @author yoshizaki
 *
 */
public class Main {
    public static void main(String[] args) {
        Scanner scanner= new Scanner(System.in);
        int num = scanner.nextInt();
        List<Double> values = new ArrayList<Double>();
        for (int i = 0 ; i < num ; i++) {
            values.add(scanner.nextDouble());
        }
        Collections.sort(values);
        for(int i = 0; i < num-1 ; i++) {
            Double v = (values.get(i) + values.get(i+1))/2;
            values.set(i+1, v);
        }
        System.out.println( values.get(num-1));
    
    
        
    }
}