import java.io.*;
import java.util.*;

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

class Main{
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		if(n == 1) {
		    System.out.println(sc.nextInt());
		}
		else {
		    int[] a = new int[n];
		    for(int i=0;i<n;i++) a[i] = sc.nextInt();
		    Arrays.sort(a);
		    double cur = (a[0]+a[1]) / 2.0;
		    for(int i=2;i<n;i++) {
		        cur = (cur + a[i]) / 2.0;
		    }
		    System.out.println(cur);
		}
	}
}