import java.util.*;
 
class Main {	
    public static void main(String args[]) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        int[] v = new int[N];
        for (int i = 0; i < N; i++) {
        	v[i] = sc.nextInt();
        }
        Arrays.sort(v);
        double x = (v[0] + v[1]) / 2.0;
        for (int i = 2; i < N; i++) {
        		x = (v[i] + x) / 2;
        	}
        System.out.println(x);
    }
} import java.util.*; util.* java class Main {	
    public static void main(String args[]) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        int[] v = new int[N];
        for (int i = 0; i < N; i++) {
        	v[i] = sc.nextInt();
        }
        Arrays.sort(v);
        double x = (v[0] + v[1]) / 2.0;
        for (int i = 2; i < N; i++) {
        		x = (v[i] + x) / 2;
        	}
        System.out.println(x);
    }
} Main public static void main(String args[]) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        int[] v = new int[N];
        for (int i = 0; i < N; i++) {
        	v[i] = sc.nextInt();
        }
        Arrays.sort(v);
        double x = (v[0] + v[1]) / 2.0;
        for (int i = 2; i < N; i++) {
        		x = (v[i] + x) / 2;
        	}
        System.out.println(x);
    } main {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        int[] v = new int[N];
        for (int i = 0; i < N; i++) {
        	v[i] = sc.nextInt();
        }
        Arrays.sort(v);
        double x = (v[0] + v[1]) / 2.0;
        for (int i = 2; i < N; i++) {
        		x = (v[i] + x) / 2;
        	}
        System.out.println(x);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc int[] v = new int[N]; v new int[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 x = (v[0] + v[1]) / 2.0; x (v[0] + v[1]) / 2.0 (v[0] + v[1]) v[0] v 0 v[1] v 1 2.0 for (int i = 2; i < N; i++) {
        		x = (v[i] + x) / 2;
        	} int i = 2; int i = 2; i 2 i < N i N i++ i++ i {
        		x = (v[i] + x) / 2;
        	} {
        		x = (v[i] + x) / 2;
        	} x = (v[i] + x) / 2 x (v[i] + x) / 2 (v[i] + x) v[i] v i x 2 System.out.println(x) System.out.println System.out System System.out x String args[] args
import java.util.*;
 
class Main {	
    public static void main(String args[]) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        int[] v = new int[N];
        for (int i = 0; i < N; i++) {
        	v[i] = sc.nextInt();
        }
        Arrays.sort(v);
        double x = (v[0] + v[1]) / 2.0;
        for (int i = 2; i < N; i++) {
        		x = (v[i] + x) / 2;
        	}
        System.out.println(x);
    }
}