import java.util.*;

class Main{
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        double[] stf = new double[n];

        for(int i = 0;i < n;i++){
            stf[i] = sc.nextDouble();
        }

        Arrays.sort(stf);

        for(int i = 0;i < n-1;i++){
            stf[i+1] = (stf[i]+stf[i+1])/2.0;
        }
        
        System.out.println(stf[n-1]);

    }
} import java.util.*; util.* java class Main{
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        double[] stf = new double[n];

        for(int i = 0;i < n;i++){
            stf[i] = sc.nextDouble();
        }

        Arrays.sort(stf);

        for(int i = 0;i < n-1;i++){
            stf[i+1] = (stf[i]+stf[i+1])/2.0;
        }
        
        System.out.println(stf[n-1]);

    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        double[] stf = new double[n];

        for(int i = 0;i < n;i++){
            stf[i] = sc.nextDouble();
        }

        Arrays.sort(stf);

        for(int i = 0;i < n-1;i++){
            stf[i+1] = (stf[i]+stf[i+1])/2.0;
        }
        
        System.out.println(stf[n-1]);

    } main {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        double[] stf = new double[n];

        for(int i = 0;i < n;i++){
            stf[i] = sc.nextDouble();
        }

        Arrays.sort(stf);

        for(int i = 0;i < n-1;i++){
            stf[i+1] = (stf[i]+stf[i+1])/2.0;
        }
        
        System.out.println(stf[n-1]);

    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc double[] stf = new double[n]; stf new double[n] n for(int i = 0;i < n;i++){
            stf[i] = sc.nextDouble();
        } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
            stf[i] = sc.nextDouble();
        } {
            stf[i] = sc.nextDouble();
        } stf[i] = sc.nextDouble() stf[i] stf i sc.nextDouble() sc.nextDouble sc Arrays.sort(stf) Arrays.sort Arrays stf for(int i = 0;i < n-1;i++){
            stf[i+1] = (stf[i]+stf[i+1])/2.0;
        } int i = 0; int i = 0; i 0 i < n-1 i n-1 n 1 i++ i++ i {
            stf[i+1] = (stf[i]+stf[i+1])/2.0;
        } {
            stf[i+1] = (stf[i]+stf[i+1])/2.0;
        } stf[i+1] = (stf[i]+stf[i+1])/2.0 stf[i+1] stf i+1 i 1 (stf[i]+stf[i+1])/2.0 (stf[i]+stf[i+1]) stf[i] stf i stf[i+1] stf i+1 i 1 2.0 System.out.println(stf[n-1]) System.out.println System.out System System.out stf[n-1] stf n-1 n 1 String[] args args
import java.util.*;

class Main{
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        double[] stf = new double[n];

        for(int i = 0;i < n;i++){
            stf[i] = sc.nextDouble();
        }

        Arrays.sort(stf);

        for(int i = 0;i < n-1;i++){
            stf[i+1] = (stf[i]+stf[i+1])/2.0;
        }
        
        System.out.println(stf[n-1]);

    }
}