import java.math.BigDecimal;
import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        List<BigDecimal> list = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            list.add(new BigDecimal(sc.next()));
        }
        Collections.sort(list);
        Deque<BigDecimal> d = new ArrayDeque();
        for (BigDecimal b : list) {
            d.add(b);
        }
        while (d.size() > 1) {
            BigDecimal x = d.poll();
            BigDecimal y = d.poll();
            d.addFirst(y.add(x).divide(new BigDecimal(2)));
        }
        System.out.println(d.poll());
    }
} import java.math.BigDecimal; BigDecimal java.math import java.util.*; util.* java public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        List<BigDecimal> list = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            list.add(new BigDecimal(sc.next()));
        }
        Collections.sort(list);
        Deque<BigDecimal> d = new ArrayDeque();
        for (BigDecimal b : list) {
            d.add(b);
        }
        while (d.size() > 1) {
            BigDecimal x = d.poll();
            BigDecimal y = d.poll();
            d.addFirst(y.add(x).divide(new BigDecimal(2)));
        }
        System.out.println(d.poll());
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        List<BigDecimal> list = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            list.add(new BigDecimal(sc.next()));
        }
        Collections.sort(list);
        Deque<BigDecimal> d = new ArrayDeque();
        for (BigDecimal b : list) {
            d.add(b);
        }
        while (d.size() > 1) {
            BigDecimal x = d.poll();
            BigDecimal y = d.poll();
            d.addFirst(y.add(x).divide(new BigDecimal(2)));
        }
        System.out.println(d.poll());
    } main {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        List<BigDecimal> list = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            list.add(new BigDecimal(sc.next()));
        }
        Collections.sort(list);
        Deque<BigDecimal> d = new ArrayDeque();
        for (BigDecimal b : list) {
            d.add(b);
        }
        while (d.size() > 1) {
            BigDecimal x = d.poll();
            BigDecimal y = d.poll();
            d.addFirst(y.add(x).divide(new BigDecimal(2)));
        }
        System.out.println(d.poll());
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc List<BigDecimal> list = new ArrayList<>(); list new ArrayList<>() for (int i = 0; i < n; i++) {
            list.add(new BigDecimal(sc.next()));
        } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
            list.add(new BigDecimal(sc.next()));
        } {
            list.add(new BigDecimal(sc.next()));
        } list.add(new BigDecimal(sc.next())) list.add list new BigDecimal(sc.next()) Collections.sort(list) Collections.sort Collections list Deque<BigDecimal> d = new ArrayDeque(); d new ArrayDeque() for (BigDecimal b : list) {
            d.add(b);
        } BigDecimal b list {
            d.add(b);
        } {
            d.add(b);
        } d.add(b) d.add d b while (d.size() > 1) {
            BigDecimal x = d.poll();
            BigDecimal y = d.poll();
            d.addFirst(y.add(x).divide(new BigDecimal(2)));
        } d.size() > 1 d.size() d.size d 1 {
            BigDecimal x = d.poll();
            BigDecimal y = d.poll();
            d.addFirst(y.add(x).divide(new BigDecimal(2)));
        } BigDecimal x = d.poll(); x d.poll() d.poll d BigDecimal y = d.poll(); y d.poll() d.poll d d.addFirst(y.add(x).divide(new BigDecimal(2))) d.addFirst d y.add(x).divide(new BigDecimal(2)) y.add(x).divide y.add(x) y.add y x new BigDecimal(2) System.out.println(d.poll()) System.out.println System.out System System.out d.poll() d.poll d String[] args args public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        List<BigDecimal> list = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            list.add(new BigDecimal(sc.next()));
        }
        Collections.sort(list);
        Deque<BigDecimal> d = new ArrayDeque();
        for (BigDecimal b : list) {
            d.add(b);
        }
        while (d.size() > 1) {
            BigDecimal x = d.poll();
            BigDecimal y = d.poll();
            d.addFirst(y.add(x).divide(new BigDecimal(2)));
        }
        System.out.println(d.poll());
    }
} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        List<BigDecimal> list = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            list.add(new BigDecimal(sc.next()));
        }
        Collections.sort(list);
        Deque<BigDecimal> d = new ArrayDeque();
        for (BigDecimal b : list) {
            d.add(b);
        }
        while (d.size() > 1) {
            BigDecimal x = d.poll();
            BigDecimal y = d.poll();
            d.addFirst(y.add(x).divide(new BigDecimal(2)));
        }
        System.out.println(d.poll());
    }
} Main
import java.math.BigDecimal;
import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        List<BigDecimal> list = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            list.add(new BigDecimal(sc.next()));
        }
        Collections.sort(list);
        Deque<BigDecimal> d = new ArrayDeque();
        for (BigDecimal b : list) {
            d.add(b);
        }
        while (d.size() > 1) {
            BigDecimal x = d.poll();
            BigDecimal y = d.poll();
            d.addFirst(y.add(x).divide(new BigDecimal(2)));
        }
        System.out.println(d.poll());
    }
}