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

// https://atcoder.jp/contests/abc138/tasks/abc138_c
public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();

		int[] arrayV = new int[N];
		for(int i=0;i<arrayV.length;i++) {
			arrayV[i] = sc.nextInt();
		}
		sc.close();

		Arrays.sort(arrayV);

		double ans = arrayV[0];

		for(int i = 1;i<N;i++) {
			ans = (ans + arrayV[i])/2;

		}

		System.out.println(ans);

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

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();

		int[] arrayV = new int[N];
		for(int i=0;i<arrayV.length;i++) {
			arrayV[i] = sc.nextInt();
		}
		sc.close();

		Arrays.sort(arrayV);

		double ans = arrayV[0];

		for(int i = 1;i<N;i++) {
			ans = (ans + arrayV[i])/2;

		}

		System.out.println(ans);

	}
} Main public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();

		int[] arrayV = new int[N];
		for(int i=0;i<arrayV.length;i++) {
			arrayV[i] = sc.nextInt();
		}
		sc.close();

		Arrays.sort(arrayV);

		double ans = arrayV[0];

		for(int i = 1;i<N;i++) {
			ans = (ans + arrayV[i])/2;

		}

		System.out.println(ans);

	} main {
		// TODO 自動生成されたメソッド・スタブ
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();

		int[] arrayV = new int[N];
		for(int i=0;i<arrayV.length;i++) {
			arrayV[i] = sc.nextInt();
		}
		sc.close();

		Arrays.sort(arrayV);

		double ans = arrayV[0];

		for(int i = 1;i<N;i++) {
			ans = (ans + arrayV[i])/2;

		}

		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 int[] arrayV = new int[N]; arrayV new int[N] N for(int i=0;i<arrayV.length;i++) {
			arrayV[i] = sc.nextInt();
		} int i=0; int i=0; i 0 i<arrayV.length i arrayV.length arrayV arrayV.length i++ i++ i {
			arrayV[i] = sc.nextInt();
		} {
			arrayV[i] = sc.nextInt();
		} arrayV[i] = sc.nextInt() arrayV[i] arrayV i sc.nextInt() sc.nextInt sc sc.close() sc.close sc Arrays.sort(arrayV) Arrays.sort Arrays arrayV double ans = arrayV[0]; ans arrayV[0] arrayV 0 for(int i = 1;i<N;i++) {
			ans = (ans + arrayV[i])/2;

		} int i = 1; int i = 1; i 1 i<N i N i++ i++ i {
			ans = (ans + arrayV[i])/2;

		} {
			ans = (ans + arrayV[i])/2;

		} ans = (ans + arrayV[i])/2 ans (ans + arrayV[i])/2 (ans + arrayV[i]) ans arrayV[i] arrayV i 2 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) {
		// TODO 自動生成されたメソッド・スタブ
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();

		int[] arrayV = new int[N];
		for(int i=0;i<arrayV.length;i++) {
			arrayV[i] = sc.nextInt();
		}
		sc.close();

		Arrays.sort(arrayV);

		double ans = arrayV[0];

		for(int i = 1;i<N;i++) {
			ans = (ans + arrayV[i])/2;

		}

		System.out.println(ans);

	}
} public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();

		int[] arrayV = new int[N];
		for(int i=0;i<arrayV.length;i++) {
			arrayV[i] = sc.nextInt();
		}
		sc.close();

		Arrays.sort(arrayV);

		double ans = arrayV[0];

		for(int i = 1;i<N;i++) {
			ans = (ans + arrayV[i])/2;

		}

		System.out.println(ans);

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

// https://atcoder.jp/contests/abc138/tasks/abc138_c
public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();

		int[] arrayV = new int[N];
		for(int i=0;i<arrayV.length;i++) {
			arrayV[i] = sc.nextInt();
		}
		sc.close();

		Arrays.sort(arrayV);

		double ans = arrayV[0];

		for(int i = 1;i<N;i++) {
			ans = (ans + arrayV[i])/2;

		}

		System.out.println(ans);

	}
}
