import java.util.Arrays;
import java.util.Scanner;

	public class Main {

		public static void main(String[] args) {
			// AtCoder_C
			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();
			}

			for(int i=0; i<N-1; i++) {
				Arrays.parallelSort(v);
				v[0] = (v[0] + v[1]) / 2;
				v[1] = 9999;
			}

    		System.out.println(v[0]);

    	    // Scannerクラスのインスタンスをクローズ
    		sc.close();
    	}

    } import java.util.Arrays; Arrays java.util import java.util.Scanner; Scanner java.util public class Main {

		public static void main(String[] args) {
			// AtCoder_C
			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();
			}

			for(int i=0; i<N-1; i++) {
				Arrays.parallelSort(v);
				v[0] = (v[0] + v[1]) / 2;
				v[1] = 9999;
			}

    		System.out.println(v[0]);

    	    // Scannerクラスのインスタンスをクローズ
    		sc.close();
    	}

    } Main public static void main(String[] args) {
			// AtCoder_C
			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();
			}

			for(int i=0; i<N-1; i++) {
				Arrays.parallelSort(v);
				v[0] = (v[0] + v[1]) / 2;
				v[1] = 9999;
			}

    		System.out.println(v[0]);

    	    // Scannerクラスのインスタンスをクローズ
    		sc.close();
    	} main {
			// AtCoder_C
			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();
			}

			for(int i=0; i<N-1; i++) {
				Arrays.parallelSort(v);
				v[0] = (v[0] + v[1]) / 2;
				v[1] = 9999;
			}

    		System.out.println(v[0]);

    	    // Scannerクラスのインスタンスをクローズ
    		sc.close();
    	} 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 for(int i=0; i<N-1; i++) {
				Arrays.parallelSort(v);
				v[0] = (v[0] + v[1]) / 2;
				v[1] = 9999;
			} int i=0; int i=0; i 0 i<N-1 i N-1 N 1 i++ i++ i {
				Arrays.parallelSort(v);
				v[0] = (v[0] + v[1]) / 2;
				v[1] = 9999;
			} {
				Arrays.parallelSort(v);
				v[0] = (v[0] + v[1]) / 2;
				v[1] = 9999;
			} Arrays.parallelSort(v) Arrays.parallelSort Arrays v v[0] = (v[0] + v[1]) / 2 v[0] v 0 (v[0] + v[1]) / 2 (v[0] + v[1]) v[0] v 0 v[1] v 1 2 v[1] = 9999 v[1] v 1 9999 System.out.println(v[0]) System.out.println System.out System System.out v[0] v 0 sc.close() sc.close sc String[] args args public class Main {

		public static void main(String[] args) {
			// AtCoder_C
			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();
			}

			for(int i=0; i<N-1; i++) {
				Arrays.parallelSort(v);
				v[0] = (v[0] + v[1]) / 2;
				v[1] = 9999;
			}

    		System.out.println(v[0]);

    	    // Scannerクラスのインスタンスをクローズ
    		sc.close();
    	}

    } public class Main {

		public static void main(String[] args) {
			// AtCoder_C
			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();
			}

			for(int i=0; i<N-1; i++) {
				Arrays.parallelSort(v);
				v[0] = (v[0] + v[1]) / 2;
				v[1] = 9999;
			}

    		System.out.println(v[0]);

    	    // Scannerクラスのインスタンスをクローズ
    		sc.close();
    	}

    } Main
import java.util.Arrays;
import java.util.Scanner;

	public class Main {

		public static void main(String[] args) {
			// AtCoder_C
			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();
			}

			for(int i=0; i<N-1; i++) {
				Arrays.parallelSort(v);
				v[0] = (v[0] + v[1]) / 2;
				v[1] = 9999;
			}

    		System.out.println(v[0]);

    	    // Scannerクラスのインスタンスをクローズ
    		sc.close();
    	}

    }