import java.util.*;

public class Main {
	static int N=26;
	public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		N = sc.nextInt();
		int data[] =new int[N];

		ArrayList<Double> ar =new ArrayList<Double>();
	
		for(int i=0;i<data.length;i++) {
			double a=sc.nextInt();
			ar.add(a);
		}
		Collections.sort(ar);
		double tt=ar.get(0);
		ar.remove(0);
		while(true) {
			double t1 =tt+ar.get(0);
			tt= (double)t1 / 2.0;
			ar.remove(0);
			
			if(ar.size()==0)break;
		}
		System.out.println(tt);
		
		
		

	}

} import java.util.*; util.* java public class Main {
	static int N=26;
	public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		N = sc.nextInt();
		int data[] =new int[N];

		ArrayList<Double> ar =new ArrayList<Double>();
	
		for(int i=0;i<data.length;i++) {
			double a=sc.nextInt();
			ar.add(a);
		}
		Collections.sort(ar);
		double tt=ar.get(0);
		ar.remove(0);
		while(true) {
			double t1 =tt+ar.get(0);
			tt= (double)t1 / 2.0;
			ar.remove(0);
			
			if(ar.size()==0)break;
		}
		System.out.println(tt);
		
		
		

	}

} Main static int N=26; N 26 public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		N = sc.nextInt();
		int data[] =new int[N];

		ArrayList<Double> ar =new ArrayList<Double>();
	
		for(int i=0;i<data.length;i++) {
			double a=sc.nextInt();
			ar.add(a);
		}
		Collections.sort(ar);
		double tt=ar.get(0);
		ar.remove(0);
		while(true) {
			double t1 =tt+ar.get(0);
			tt= (double)t1 / 2.0;
			ar.remove(0);
			
			if(ar.size()==0)break;
		}
		System.out.println(tt);
		
		
		

	} main {
		Scanner sc = new Scanner(System.in);
		N = sc.nextInt();
		int data[] =new int[N];

		ArrayList<Double> ar =new ArrayList<Double>();
	
		for(int i=0;i<data.length;i++) {
			double a=sc.nextInt();
			ar.add(a);
		}
		Collections.sort(ar);
		double tt=ar.get(0);
		ar.remove(0);
		while(true) {
			double t1 =tt+ar.get(0);
			tt= (double)t1 / 2.0;
			ar.remove(0);
			
			if(ar.size()==0)break;
		}
		System.out.println(tt);
		
		
		

	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) N = sc.nextInt() N sc.nextInt() sc.nextInt sc int data[] =new int[N]; data new int[N] N ArrayList<Double> ar =new ArrayList<Double>(); ar new ArrayList<Double>() for(int i=0;i<data.length;i++) {
			double a=sc.nextInt();
			ar.add(a);
		} int i=0; int i=0; i 0 i<data.length i data.length data data.length i++ i++ i {
			double a=sc.nextInt();
			ar.add(a);
		} {
			double a=sc.nextInt();
			ar.add(a);
		} double a=sc.nextInt(); a sc.nextInt() sc.nextInt sc ar.add(a) ar.add ar a Collections.sort(ar) Collections.sort Collections ar double tt=ar.get(0); tt ar.get(0) ar.get ar 0 ar.remove(0) ar.remove ar 0 while(true) {
			double t1 =tt+ar.get(0);
			tt= (double)t1 / 2.0;
			ar.remove(0);
			
			if(ar.size()==0)break;
		} true {
			double t1 =tt+ar.get(0);
			tt= (double)t1 / 2.0;
			ar.remove(0);
			
			if(ar.size()==0)break;
		} double t1 =tt+ar.get(0); t1 tt+ar.get(0) tt ar.get(0) ar.get ar 0 tt= (double)t1 / 2.0 tt (double)t1 / 2.0 (double)t1 2.0 ar.remove(0) ar.remove ar 0 if(ar.size()==0)break; ar.size()==0 ar.size() ar.size ar 0 break; System.out.println(tt) System.out.println System.out System System.out tt String args[] args public class Main {
	static int N=26;
	public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		N = sc.nextInt();
		int data[] =new int[N];

		ArrayList<Double> ar =new ArrayList<Double>();
	
		for(int i=0;i<data.length;i++) {
			double a=sc.nextInt();
			ar.add(a);
		}
		Collections.sort(ar);
		double tt=ar.get(0);
		ar.remove(0);
		while(true) {
			double t1 =tt+ar.get(0);
			tt= (double)t1 / 2.0;
			ar.remove(0);
			
			if(ar.size()==0)break;
		}
		System.out.println(tt);
		
		
		

	}

} public class Main {
	static int N=26;
	public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		N = sc.nextInt();
		int data[] =new int[N];

		ArrayList<Double> ar =new ArrayList<Double>();
	
		for(int i=0;i<data.length;i++) {
			double a=sc.nextInt();
			ar.add(a);
		}
		Collections.sort(ar);
		double tt=ar.get(0);
		ar.remove(0);
		while(true) {
			double t1 =tt+ar.get(0);
			tt= (double)t1 / 2.0;
			ar.remove(0);
			
			if(ar.size()==0)break;
		}
		System.out.println(tt);
		
		
		

	}

} Main
import java.util.*;

public class Main {
	static int N=26;
	public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		N = sc.nextInt();
		int data[] =new int[N];

		ArrayList<Double> ar =new ArrayList<Double>();
	
		for(int i=0;i<data.length;i++) {
			double a=sc.nextInt();
			ar.add(a);
		}
		Collections.sort(ar);
		double tt=ar.get(0);
		ar.remove(0);
		while(true) {
			double t1 =tt+ar.get(0);
			tt= (double)t1 / 2.0;
			ar.remove(0);
			
			if(ar.size()==0)break;
		}
		System.out.println(tt);
		
		
		

	}

}
