import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Arrays;

public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.solve(args);
    }

    public void solve(String[] args) {
        MyScanner scanner = new MyScanner();
        int n = scanner.nextInt();
        double[] array = new double[n];

        for(int i=0;i<n;i++) {
        	array[i] = scanner.nextDouble();
        }
        Arrays.sort(array);

        double tmp = 0;
        for(int i=0;i<n;i++) {
        	if(i==0) {
        		tmp = array[i];
        	}else {
        		tmp = (tmp + array[i])/2;
        	}
        }
        System.out.println(tmp);
    }

    private static long gcd(long m, long n) {
        if(m < n) return gcd(n, m);
        if(n == 0) return m;
        return gcd(n, m % n);
    }

    private static long lcm(long m, long n) {
        return m * n / gcd(m, n);
    }

    private class MyScanner {
        String[] s;
        int i;
        BufferedReader br;
        String reg = " ";
        MyScanner () {
            s = new String[0];
            i = 0;
            br = new BufferedReader(new InputStreamReader(System.in));
        }
        public String next() {
            try {
                if (i < s.length) return s[i++];
                String line = br.readLine();
                while (line.equals("")) {line = br.readLine();}
                s = line.split(reg, 0);
                i = 0;return s[i++];
            } catch (Exception e) {e.printStackTrace();}
            return null;
        }
        public int nextInt() {
            try {return Integer.parseInt(next());} catch (Exception e) {e.printStackTrace();}
            return -1;
        }
        public double nextDouble() {
            try {return Double.parseDouble(next());} catch (Exception e) {e.printStackTrace();}
            return -1;
        }
        public long nextLong()  {
            try {return Long.parseLong(next());} catch (Exception e) {e.printStackTrace();}
            return -1;
        }
    }
} import java.io.BufferedReader; BufferedReader java.io import java.io.InputStreamReader; InputStreamReader java.io import java.util.Arrays; Arrays java.util public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.solve(args);
    }

    public void solve(String[] args) {
        MyScanner scanner = new MyScanner();
        int n = scanner.nextInt();
        double[] array = new double[n];

        for(int i=0;i<n;i++) {
        	array[i] = scanner.nextDouble();
        }
        Arrays.sort(array);

        double tmp = 0;
        for(int i=0;i<n;i++) {
        	if(i==0) {
        		tmp = array[i];
        	}else {
        		tmp = (tmp + array[i])/2;
        	}
        }
        System.out.println(tmp);
    }

    private static long gcd(long m, long n) {
        if(m < n) return gcd(n, m);
        if(n == 0) return m;
        return gcd(n, m % n);
    }

    private static long lcm(long m, long n) {
        return m * n / gcd(m, n);
    }

    private class MyScanner {
        String[] s;
        int i;
        BufferedReader br;
        String reg = " ";
        MyScanner () {
            s = new String[0];
            i = 0;
            br = new BufferedReader(new InputStreamReader(System.in));
        }
        public String next() {
            try {
                if (i < s.length) return s[i++];
                String line = br.readLine();
                while (line.equals("")) {line = br.readLine();}
                s = line.split(reg, 0);
                i = 0;return s[i++];
            } catch (Exception e) {e.printStackTrace();}
            return null;
        }
        public int nextInt() {
            try {return Integer.parseInt(next());} catch (Exception e) {e.printStackTrace();}
            return -1;
        }
        public double nextDouble() {
            try {return Double.parseDouble(next());} catch (Exception e) {e.printStackTrace();}
            return -1;
        }
        public long nextLong()  {
            try {return Long.parseLong(next());} catch (Exception e) {e.printStackTrace();}
            return -1;
        }
    }
} Main public static void main(String[] args) {
        Main main = new Main();
        main.solve(args);
    } main {
        Main main = new Main();
        main.solve(args);
    } Main main = new Main(); main new Main() main.solve(args) main.solve main args String[] args args public void solve(String[] args) {
        MyScanner scanner = new MyScanner();
        int n = scanner.nextInt();
        double[] array = new double[n];

        for(int i=0;i<n;i++) {
        	array[i] = scanner.nextDouble();
        }
        Arrays.sort(array);

        double tmp = 0;
        for(int i=0;i<n;i++) {
        	if(i==0) {
        		tmp = array[i];
        	}else {
        		tmp = (tmp + array[i])/2;
        	}
        }
        System.out.println(tmp);
    } solve {
        MyScanner scanner = new MyScanner();
        int n = scanner.nextInt();
        double[] array = new double[n];

        for(int i=0;i<n;i++) {
        	array[i] = scanner.nextDouble();
        }
        Arrays.sort(array);

        double tmp = 0;
        for(int i=0;i<n;i++) {
        	if(i==0) {
        		tmp = array[i];
        	}else {
        		tmp = (tmp + array[i])/2;
        	}
        }
        System.out.println(tmp);
    } MyScanner scanner = new MyScanner(); scanner new MyScanner() int n = scanner.nextInt(); n scanner.nextInt() scanner.nextInt scanner double[] array = new double[n]; array new double[n] n for(int i=0;i<n;i++) {
        	array[i] = scanner.nextDouble();
        } int i=0; int i=0; i 0 i<n i n i++ i++ i {
        	array[i] = scanner.nextDouble();
        } {
        	array[i] = scanner.nextDouble();
        } array[i] = scanner.nextDouble() array[i] array i scanner.nextDouble() scanner.nextDouble scanner Arrays.sort(array) Arrays.sort Arrays array double tmp = 0; tmp 0 for(int i=0;i<n;i++) {
        	if(i==0) {
        		tmp = array[i];
        	}else {
        		tmp = (tmp + array[i])/2;
        	}
        } int i=0; int i=0; i 0 i<n i n i++ i++ i {
        	if(i==0) {
        		tmp = array[i];
        	}else {
        		tmp = (tmp + array[i])/2;
        	}
        } {
        	if(i==0) {
        		tmp = array[i];
        	}else {
        		tmp = (tmp + array[i])/2;
        	}
        } if(i==0) {
        		tmp = array[i];
        	}else {
        		tmp = (tmp + array[i])/2;
        	} i==0 i 0 {
        		tmp = array[i];
        	} tmp = array[i] tmp array[i] array i {
        		tmp = (tmp + array[i])/2;
        	} tmp = (tmp + array[i])/2 tmp (tmp + array[i])/2 (tmp + array[i]) tmp array[i] array i 2 System.out.println(tmp) System.out.println System.out System System.out tmp String[] args args private static long gcd(long m, long n) {
        if(m < n) return gcd(n, m);
        if(n == 0) return m;
        return gcd(n, m % n);
    } gcd {
        if(m < n) return gcd(n, m);
        if(n == 0) return m;
        return gcd(n, m % n);
    } if(m < n) return gcd(n, m); m < n m n return gcd(n, m); gcd(n, m) gcd n m if(n == 0) return m; n == 0 n 0 return m; m return gcd(n, m % n); gcd(n, m % n) gcd n m % n m n long m m long n n private static long lcm(long m, long n) {
        return m * n / gcd(m, n);
    } lcm {
        return m * n / gcd(m, n);
    } return m * n / gcd(m, n); m * n / gcd(m, n) m * n m n gcd(m, n) gcd m n long m m long n n private class MyScanner {
        String[] s;
        int i;
        BufferedReader br;
        String reg = " ";
        MyScanner () {
            s = new String[0];
            i = 0;
            br = new BufferedReader(new InputStreamReader(System.in));
        }
        public String next() {
            try {
                if (i < s.length) return s[i++];
                String line = br.readLine();
                while (line.equals("")) {line = br.readLine();}
                s = line.split(reg, 0);
                i = 0;return s[i++];
            } catch (Exception e) {e.printStackTrace();}
            return null;
        }
        public int nextInt() {
            try {return Integer.parseInt(next());} catch (Exception e) {e.printStackTrace();}
            return -1;
        }
        public double nextDouble() {
            try {return Double.parseDouble(next());} catch (Exception e) {e.printStackTrace();}
            return -1;
        }
        public long nextLong()  {
            try {return Long.parseLong(next());} catch (Exception e) {e.printStackTrace();}
            return -1;
        }
    } MyScanner String[] s; s int i; i BufferedReader br; br String reg = " "; reg " " MyScanner () {
            s = new String[0];
            i = 0;
            br = new BufferedReader(new InputStreamReader(System.in));
        } MyScanner {
            s = new String[0];
            i = 0;
            br = new BufferedReader(new InputStreamReader(System.in));
        } s = new String[0] s new String[0] 0 i = 0 i 0 br = new BufferedReader(new InputStreamReader(System.in)) br new BufferedReader(new InputStreamReader(System.in)) public String next() {
            try {
                if (i < s.length) return s[i++];
                String line = br.readLine();
                while (line.equals("")) {line = br.readLine();}
                s = line.split(reg, 0);
                i = 0;return s[i++];
            } catch (Exception e) {e.printStackTrace();}
            return null;
        } next {
            try {
                if (i < s.length) return s[i++];
                String line = br.readLine();
                while (line.equals("")) {line = br.readLine();}
                s = line.split(reg, 0);
                i = 0;return s[i++];
            } catch (Exception e) {e.printStackTrace();}
            return null;
        } try {
                if (i < s.length) return s[i++];
                String line = br.readLine();
                while (line.equals("")) {line = br.readLine();}
                s = line.split(reg, 0);
                i = 0;return s[i++];
            } catch (Exception e) {e.printStackTrace();} catch (Exception e) {e.printStackTrace();} Exception e {e.printStackTrace();} e.printStackTrace() e.printStackTrace e {
                if (i < s.length) return s[i++];
                String line = br.readLine();
                while (line.equals("")) {line = br.readLine();}
                s = line.split(reg, 0);
                i = 0;return s[i++];
            } if (i < s.length) return s[i++]; i < s.length i s.length s s.length return s[i++]; s[i++] s i++ i String line = br.readLine(); line br.readLine() br.readLine br while (line.equals("")) {line = br.readLine();} line.equals("") line.equals line "" {line = br.readLine();} line = br.readLine() line br.readLine() br.readLine br s = line.split(reg, 0) s line.split(reg, 0) line.split line reg 0 i = 0 i 0 return s[i++]; s[i++] s i++ i return null; null public int nextInt() {
            try {return Integer.parseInt(next());} catch (Exception e) {e.printStackTrace();}
            return -1;
        } nextInt {
            try {return Integer.parseInt(next());} catch (Exception e) {e.printStackTrace();}
            return -1;
        } try {return Integer.parseInt(next());} catch (Exception e) {e.printStackTrace();} catch (Exception e) {e.printStackTrace();} Exception e {e.printStackTrace();} e.printStackTrace() e.printStackTrace e {return Integer.parseInt(next());} return Integer.parseInt(next()); Integer.parseInt(next()) Integer.parseInt Integer next() next return -1; -1 1 public double nextDouble() {
            try {return Double.parseDouble(next());} catch (Exception e) {e.printStackTrace();}
            return -1;
        } nextDouble {
            try {return Double.parseDouble(next());} catch (Exception e) {e.printStackTrace();}
            return -1;
        } try {return Double.parseDouble(next());} catch (Exception e) {e.printStackTrace();} catch (Exception e) {e.printStackTrace();} Exception e {e.printStackTrace();} e.printStackTrace() e.printStackTrace e {return Double.parseDouble(next());} return Double.parseDouble(next()); Double.parseDouble(next()) Double.parseDouble Double next() next return -1; -1 1 public long nextLong()  {
            try {return Long.parseLong(next());} catch (Exception e) {e.printStackTrace();}
            return -1;
        } nextLong {
            try {return Long.parseLong(next());} catch (Exception e) {e.printStackTrace();}
            return -1;
        } try {return Long.parseLong(next());} catch (Exception e) {e.printStackTrace();} catch (Exception e) {e.printStackTrace();} Exception e {e.printStackTrace();} e.printStackTrace() e.printStackTrace e {return Long.parseLong(next());} return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next return -1; -1 1 public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.solve(args);
    }

    public void solve(String[] args) {
        MyScanner scanner = new MyScanner();
        int n = scanner.nextInt();
        double[] array = new double[n];

        for(int i=0;i<n;i++) {
        	array[i] = scanner.nextDouble();
        }
        Arrays.sort(array);

        double tmp = 0;
        for(int i=0;i<n;i++) {
        	if(i==0) {
        		tmp = array[i];
        	}else {
        		tmp = (tmp + array[i])/2;
        	}
        }
        System.out.println(tmp);
    }

    private static long gcd(long m, long n) {
        if(m < n) return gcd(n, m);
        if(n == 0) return m;
        return gcd(n, m % n);
    }

    private static long lcm(long m, long n) {
        return m * n / gcd(m, n);
    }

    private class MyScanner {
        String[] s;
        int i;
        BufferedReader br;
        String reg = " ";
        MyScanner () {
            s = new String[0];
            i = 0;
            br = new BufferedReader(new InputStreamReader(System.in));
        }
        public String next() {
            try {
                if (i < s.length) return s[i++];
                String line = br.readLine();
                while (line.equals("")) {line = br.readLine();}
                s = line.split(reg, 0);
                i = 0;return s[i++];
            } catch (Exception e) {e.printStackTrace();}
            return null;
        }
        public int nextInt() {
            try {return Integer.parseInt(next());} catch (Exception e) {e.printStackTrace();}
            return -1;
        }
        public double nextDouble() {
            try {return Double.parseDouble(next());} catch (Exception e) {e.printStackTrace();}
            return -1;
        }
        public long nextLong()  {
            try {return Long.parseLong(next());} catch (Exception e) {e.printStackTrace();}
            return -1;
        }
    }
} public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.solve(args);
    }

    public void solve(String[] args) {
        MyScanner scanner = new MyScanner();
        int n = scanner.nextInt();
        double[] array = new double[n];

        for(int i=0;i<n;i++) {
        	array[i] = scanner.nextDouble();
        }
        Arrays.sort(array);

        double tmp = 0;
        for(int i=0;i<n;i++) {
        	if(i==0) {
        		tmp = array[i];
        	}else {
        		tmp = (tmp + array[i])/2;
        	}
        }
        System.out.println(tmp);
    }

    private static long gcd(long m, long n) {
        if(m < n) return gcd(n, m);
        if(n == 0) return m;
        return gcd(n, m % n);
    }

    private static long lcm(long m, long n) {
        return m * n / gcd(m, n);
    }

    private class MyScanner {
        String[] s;
        int i;
        BufferedReader br;
        String reg = " ";
        MyScanner () {
            s = new String[0];
            i = 0;
            br = new BufferedReader(new InputStreamReader(System.in));
        }
        public String next() {
            try {
                if (i < s.length) return s[i++];
                String line = br.readLine();
                while (line.equals("")) {line = br.readLine();}
                s = line.split(reg, 0);
                i = 0;return s[i++];
            } catch (Exception e) {e.printStackTrace();}
            return null;
        }
        public int nextInt() {
            try {return Integer.parseInt(next());} catch (Exception e) {e.printStackTrace();}
            return -1;
        }
        public double nextDouble() {
            try {return Double.parseDouble(next());} catch (Exception e) {e.printStackTrace();}
            return -1;
        }
        public long nextLong()  {
            try {return Long.parseLong(next());} catch (Exception e) {e.printStackTrace();}
            return -1;
        }
    }
} Main
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.Arrays;

public class Main {
    public static void main(String[] args) {
        Main main = new Main();
        main.solve(args);
    }

    public void solve(String[] args) {
        MyScanner scanner = new MyScanner();
        int n = scanner.nextInt();
        double[] array = new double[n];

        for(int i=0;i<n;i++) {
        	array[i] = scanner.nextDouble();
        }
        Arrays.sort(array);

        double tmp = 0;
        for(int i=0;i<n;i++) {
        	if(i==0) {
        		tmp = array[i];
        	}else {
        		tmp = (tmp + array[i])/2;
        	}
        }
        System.out.println(tmp);
    }

    private static long gcd(long m, long n) {
        if(m < n) return gcd(n, m);
        if(n == 0) return m;
        return gcd(n, m % n);
    }

    private static long lcm(long m, long n) {
        return m * n / gcd(m, n);
    }

    private class MyScanner {
        String[] s;
        int i;
        BufferedReader br;
        String reg = " ";
        MyScanner () {
            s = new String[0];
            i = 0;
            br = new BufferedReader(new InputStreamReader(System.in));
        }
        public String next() {
            try {
                if (i < s.length) return s[i++];
                String line = br.readLine();
                while (line.equals("")) {line = br.readLine();}
                s = line.split(reg, 0);
                i = 0;return s[i++];
            } catch (Exception e) {e.printStackTrace();}
            return null;
        }
        public int nextInt() {
            try {return Integer.parseInt(next());} catch (Exception e) {e.printStackTrace();}
            return -1;
        }
        public double nextDouble() {
            try {return Double.parseDouble(next());} catch (Exception e) {e.printStackTrace();}
            return -1;
        }
        public long nextLong()  {
            try {return Long.parseLong(next());} catch (Exception e) {e.printStackTrace();}
            return -1;
        }
    }
}