import java.util.*;

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

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