import java.io.FileNotFoundException;
import java.util.Arrays;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws FileNotFoundException {

		//    	File file = new File("src/in.txt");
		//    	Scanner sc = new Scanner(file);

		Scanner sc = new Scanner(System.in);

		int N = sc.nextInt();
		double ans = 0;
		int[] v = new int[N];
		for(int i=0;i<N;i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		for(int i=0;i<N;i++) {
			if(i==0) {
				ans = v[i];
			} else {
				ans = (ans+v[i])/2.0;
			}
		}
		System.out.printf("%.5f",ans);


	}
} import java.io.FileNotFoundException; FileNotFoundException java.io import java.util.Arrays; Arrays java.util import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) throws FileNotFoundException {

		//    	File file = new File("src/in.txt");
		//    	Scanner sc = new Scanner(file);

		Scanner sc = new Scanner(System.in);

		int N = sc.nextInt();
		double ans = 0;
		int[] v = new int[N];
		for(int i=0;i<N;i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		for(int i=0;i<N;i++) {
			if(i==0) {
				ans = v[i];
			} else {
				ans = (ans+v[i])/2.0;
			}
		}
		System.out.printf("%.5f",ans);


	}
} Main public static void main(String[] args) throws FileNotFoundException {

		//    	File file = new File("src/in.txt");
		//    	Scanner sc = new Scanner(file);

		Scanner sc = new Scanner(System.in);

		int N = sc.nextInt();
		double ans = 0;
		int[] v = new int[N];
		for(int i=0;i<N;i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		for(int i=0;i<N;i++) {
			if(i==0) {
				ans = v[i];
			} else {
				ans = (ans+v[i])/2.0;
			}
		}
		System.out.printf("%.5f",ans);


	} main {

		//    	File file = new File("src/in.txt");
		//    	Scanner sc = new Scanner(file);

		Scanner sc = new Scanner(System.in);

		int N = sc.nextInt();
		double ans = 0;
		int[] v = new int[N];
		for(int i=0;i<N;i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		for(int i=0;i<N;i++) {
			if(i==0) {
				ans = v[i];
			} else {
				ans = (ans+v[i])/2.0;
			}
		}
		System.out.printf("%.5f",ans);


	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc double ans = 0; ans 0 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 for(int i=0;i<N;i++) {
			if(i==0) {
				ans = v[i];
			} else {
				ans = (ans+v[i])/2.0;
			}
		} int i=0; int i=0; i 0 i<N i N i++ i++ i {
			if(i==0) {
				ans = v[i];
			} else {
				ans = (ans+v[i])/2.0;
			}
		} {
			if(i==0) {
				ans = v[i];
			} else {
				ans = (ans+v[i])/2.0;
			}
		} if(i==0) {
				ans = v[i];
			} else {
				ans = (ans+v[i])/2.0;
			} i==0 i 0 {
				ans = v[i];
			} ans = v[i] ans v[i] v i {
				ans = (ans+v[i])/2.0;
			} ans = (ans+v[i])/2.0 ans (ans+v[i])/2.0 (ans+v[i]) ans v[i] v i 2.0 System.out.printf("%.5f",ans) System.out.printf System.out System System.out "%.5f" ans String[] args args public class Main {
	public static void main(String[] args) throws FileNotFoundException {

		//    	File file = new File("src/in.txt");
		//    	Scanner sc = new Scanner(file);

		Scanner sc = new Scanner(System.in);

		int N = sc.nextInt();
		double ans = 0;
		int[] v = new int[N];
		for(int i=0;i<N;i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		for(int i=0;i<N;i++) {
			if(i==0) {
				ans = v[i];
			} else {
				ans = (ans+v[i])/2.0;
			}
		}
		System.out.printf("%.5f",ans);


	}
} public class Main {
	public static void main(String[] args) throws FileNotFoundException {

		//    	File file = new File("src/in.txt");
		//    	Scanner sc = new Scanner(file);

		Scanner sc = new Scanner(System.in);

		int N = sc.nextInt();
		double ans = 0;
		int[] v = new int[N];
		for(int i=0;i<N;i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		for(int i=0;i<N;i++) {
			if(i==0) {
				ans = v[i];
			} else {
				ans = (ans+v[i])/2.0;
			}
		}
		System.out.printf("%.5f",ans);


	}
} Main
import java.io.FileNotFoundException;
import java.util.Arrays;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) throws FileNotFoundException {

		//    	File file = new File("src/in.txt");
		//    	Scanner sc = new Scanner(file);

		Scanner sc = new Scanner(System.in);

		int N = sc.nextInt();
		double ans = 0;
		int[] v = new int[N];
		for(int i=0;i<N;i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		for(int i=0;i<N;i++) {
			if(i==0) {
				ans = v[i];
			} else {
				ans = (ans+v[i])/2.0;
			}
		}
		System.out.printf("%.5f",ans);


	}
}