import java.util.*;

public class Main{
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		
		ArrayList<Integer> valueList = new ArrayList<Integer>();
		for(int i = 0; i < n; ++i){
			valueList.add(sc.nextInt());
		}
		Collections.sort(valueList);
		Collections.reverse(valueList);
		
		double ans = 0.0;
		double coefficient = 1.0;
		
		for(int i = 0; i < n; ++i){
			if(i < n - 1){
				coefficient *= 0.5;
			}
			ans += valueList.get(i) * coefficient;
		}
		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();
		
		ArrayList<Integer> valueList = new ArrayList<Integer>();
		for(int i = 0; i < n; ++i){
			valueList.add(sc.nextInt());
		}
		Collections.sort(valueList);
		Collections.reverse(valueList);
		
		double ans = 0.0;
		double coefficient = 1.0;
		
		for(int i = 0; i < n; ++i){
			if(i < n - 1){
				coefficient *= 0.5;
			}
			ans += valueList.get(i) * coefficient;
		}
		System.out.println(ans);
	}
} Main public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		
		ArrayList<Integer> valueList = new ArrayList<Integer>();
		for(int i = 0; i < n; ++i){
			valueList.add(sc.nextInt());
		}
		Collections.sort(valueList);
		Collections.reverse(valueList);
		
		double ans = 0.0;
		double coefficient = 1.0;
		
		for(int i = 0; i < n; ++i){
			if(i < n - 1){
				coefficient *= 0.5;
			}
			ans += valueList.get(i) * coefficient;
		}
		System.out.println(ans);
	} main {
		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		
		ArrayList<Integer> valueList = new ArrayList<Integer>();
		for(int i = 0; i < n; ++i){
			valueList.add(sc.nextInt());
		}
		Collections.sort(valueList);
		Collections.reverse(valueList);
		
		double ans = 0.0;
		double coefficient = 1.0;
		
		for(int i = 0; i < n; ++i){
			if(i < n - 1){
				coefficient *= 0.5;
			}
			ans += valueList.get(i) * coefficient;
		}
		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 ArrayList<Integer> valueList = new ArrayList<Integer>(); valueList new ArrayList<Integer>() for(int i = 0; i < n; ++i){
			valueList.add(sc.nextInt());
		} int i = 0; int i = 0; i 0 i < n i n ++i ++i i {
			valueList.add(sc.nextInt());
		} {
			valueList.add(sc.nextInt());
		} valueList.add(sc.nextInt()) valueList.add valueList sc.nextInt() sc.nextInt sc Collections.sort(valueList) Collections.sort Collections valueList Collections.reverse(valueList) Collections.reverse Collections valueList double ans = 0.0; ans 0.0 double coefficient = 1.0; coefficient 1.0 for(int i = 0; i < n; ++i){
			if(i < n - 1){
				coefficient *= 0.5;
			}
			ans += valueList.get(i) * coefficient;
		} int i = 0; int i = 0; i 0 i < n i n ++i ++i i {
			if(i < n - 1){
				coefficient *= 0.5;
			}
			ans += valueList.get(i) * coefficient;
		} {
			if(i < n - 1){
				coefficient *= 0.5;
			}
			ans += valueList.get(i) * coefficient;
		} if(i < n - 1){
				coefficient *= 0.5;
			} i < n - 1 i n - 1 n 1 {
				coefficient *= 0.5;
			} coefficient *= 0.5 coefficient 0.5 ans += valueList.get(i) * coefficient ans valueList.get(i) * coefficient valueList.get(i) valueList.get valueList i coefficient 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();
		
		ArrayList<Integer> valueList = new ArrayList<Integer>();
		for(int i = 0; i < n; ++i){
			valueList.add(sc.nextInt());
		}
		Collections.sort(valueList);
		Collections.reverse(valueList);
		
		double ans = 0.0;
		double coefficient = 1.0;
		
		for(int i = 0; i < n; ++i){
			if(i < n - 1){
				coefficient *= 0.5;
			}
			ans += valueList.get(i) * coefficient;
		}
		System.out.println(ans);
	}
} public class Main{
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		
		ArrayList<Integer> valueList = new ArrayList<Integer>();
		for(int i = 0; i < n; ++i){
			valueList.add(sc.nextInt());
		}
		Collections.sort(valueList);
		Collections.reverse(valueList);
		
		double ans = 0.0;
		double coefficient = 1.0;
		
		for(int i = 0; i < n; ++i){
			if(i < n - 1){
				coefficient *= 0.5;
			}
			ans += valueList.get(i) * coefficient;
		}
		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();
		
		ArrayList<Integer> valueList = new ArrayList<Integer>();
		for(int i = 0; i < n; ++i){
			valueList.add(sc.nextInt());
		}
		Collections.sort(valueList);
		Collections.reverse(valueList);
		
		double ans = 0.0;
		double coefficient = 1.0;
		
		for(int i = 0; i < n; ++i){
			if(i < n - 1){
				coefficient *= 0.5;
			}
			ans += valueList.get(i) * coefficient;
		}
		System.out.println(ans);
	}
}