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