import java.util.*;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		// 入力
		int N = sc.nextInt();
		int[] v = new int[N];
		for (int i = 0; i < N; i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		double ave = v[0];
		for (int i = 1; i < N; i++) {
			ave = (ave+v[i])/2;
		}
		System.out.println(ave);
	}

	// ユークリッドの控除法(最大公約数を求める)
	private static long gcd(long a, long b) {
		if (b == 0) {
			return a;
		}
		return gcd(b, a % b);
	}

	// 複数の最大公約数を求める
	private static long gcdex(long param[]) {
		long g = gcd(param[0], param[1]);
		for (int i = 1; i < param.length-1; i++) {
			g = gcd(g, param[i+1]);
		}
		return g;
	}

	// 最小公倍数を求める
	private static long lcm(long a, long b) {
		return (a * b) / gcd(a, b);
	}

	//
	private static long all(long n, long count, int N) {
		if (count == N) {
			return count;
		}
		return all(1, count, N);
	}

} import java.util.*; util.* java public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		// 入力
		int N = sc.nextInt();
		int[] v = new int[N];
		for (int i = 0; i < N; i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		double ave = v[0];
		for (int i = 1; i < N; i++) {
			ave = (ave+v[i])/2;
		}
		System.out.println(ave);
	}

	// ユークリッドの控除法(最大公約数を求める)
	private static long gcd(long a, long b) {
		if (b == 0) {
			return a;
		}
		return gcd(b, a % b);
	}

	// 複数の最大公約数を求める
	private static long gcdex(long param[]) {
		long g = gcd(param[0], param[1]);
		for (int i = 1; i < param.length-1; i++) {
			g = gcd(g, param[i+1]);
		}
		return g;
	}

	// 最小公倍数を求める
	private static long lcm(long a, long b) {
		return (a * b) / gcd(a, b);
	}

	//
	private static long all(long n, long count, int N) {
		if (count == N) {
			return count;
		}
		return all(1, count, N);
	}

} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		// 入力
		int N = sc.nextInt();
		int[] v = new int[N];
		for (int i = 0; i < N; i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		double ave = v[0];
		for (int i = 1; i < N; i++) {
			ave = (ave+v[i])/2;
		}
		System.out.println(ave);
	} main {
		Scanner sc = new Scanner(System.in);

		// 入力
		int N = sc.nextInt();
		int[] v = new int[N];
		for (int i = 0; i < N; i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		double ave = v[0];
		for (int i = 1; i < N; i++) {
			ave = (ave+v[i])/2;
		}
		System.out.println(ave);
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc int[] v = new int[N]; v new int[N] N for (int i = 0; i < N; i++) {
			v[i] = sc.nextInt();
		} int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
			v[i] = sc.nextInt();
		} {
			v[i] = sc.nextInt();
		} v[i] = sc.nextInt() v[i] v i sc.nextInt() sc.nextInt sc Arrays.sort(v) Arrays.sort Arrays v double ave = v[0]; ave v[0] v 0 for (int i = 1; i < N; i++) {
			ave = (ave+v[i])/2;
		} int i = 1; int i = 1; i 1 i < N i N i++ i++ i {
			ave = (ave+v[i])/2;
		} {
			ave = (ave+v[i])/2;
		} ave = (ave+v[i])/2 ave (ave+v[i])/2 (ave+v[i]) ave v[i] v i 2 System.out.println(ave) System.out.println System.out System System.out ave String[] args args // ユークリッドの控除法(最大公約数を求める)
	private static long gcd(long a, long b) {
		if (b == 0) {
			return a;
		}
		return gcd(b, a % b);
	} gcd {
		if (b == 0) {
			return a;
		}
		return gcd(b, a % b);
	} if (b == 0) {
			return a;
		} b == 0 b 0 {
			return a;
		} return a; a return gcd(b, a % b); gcd(b, a % b) gcd b a % b a b long a a long b b // 複数の最大公約数を求める
	private static long gcdex(long param[]) {
		long g = gcd(param[0], param[1]);
		for (int i = 1; i < param.length-1; i++) {
			g = gcd(g, param[i+1]);
		}
		return g;
	} gcdex {
		long g = gcd(param[0], param[1]);
		for (int i = 1; i < param.length-1; i++) {
			g = gcd(g, param[i+1]);
		}
		return g;
	} long g = gcd(param[0], param[1]); g gcd(param[0], param[1]) gcd param[0] param 0 param[1] param 1 for (int i = 1; i < param.length-1; i++) {
			g = gcd(g, param[i+1]);
		} int i = 1; int i = 1; i 1 i < param.length-1 i param.length-1 param.length param param.length 1 i++ i++ i {
			g = gcd(g, param[i+1]);
		} {
			g = gcd(g, param[i+1]);
		} g = gcd(g, param[i+1]) g gcd(g, param[i+1]) gcd g param[i+1] param i+1 i 1 return g; g long param[] param // 最小公倍数を求める
	private static long lcm(long a, long b) {
		return (a * b) / gcd(a, b);
	} lcm {
		return (a * b) / gcd(a, b);
	} return (a * b) / gcd(a, b); (a * b) / gcd(a, b) (a * b) a b gcd(a, b) gcd a b long a a long b b //
	private static long all(long n, long count, int N) {
		if (count == N) {
			return count;
		}
		return all(1, count, N);
	} all {
		if (count == N) {
			return count;
		}
		return all(1, count, N);
	} if (count == N) {
			return count;
		} count == N count N {
			return count;
		} return count; count return all(1, count, N); all(1, count, N) all 1 count N long n n long count count int N N public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		// 入力
		int N = sc.nextInt();
		int[] v = new int[N];
		for (int i = 0; i < N; i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		double ave = v[0];
		for (int i = 1; i < N; i++) {
			ave = (ave+v[i])/2;
		}
		System.out.println(ave);
	}

	// ユークリッドの控除法(最大公約数を求める)
	private static long gcd(long a, long b) {
		if (b == 0) {
			return a;
		}
		return gcd(b, a % b);
	}

	// 複数の最大公約数を求める
	private static long gcdex(long param[]) {
		long g = gcd(param[0], param[1]);
		for (int i = 1; i < param.length-1; i++) {
			g = gcd(g, param[i+1]);
		}
		return g;
	}

	// 最小公倍数を求める
	private static long lcm(long a, long b) {
		return (a * b) / gcd(a, b);
	}

	//
	private static long all(long n, long count, int N) {
		if (count == N) {
			return count;
		}
		return all(1, count, N);
	}

} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		// 入力
		int N = sc.nextInt();
		int[] v = new int[N];
		for (int i = 0; i < N; i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		double ave = v[0];
		for (int i = 1; i < N; i++) {
			ave = (ave+v[i])/2;
		}
		System.out.println(ave);
	}

	// ユークリッドの控除法(最大公約数を求める)
	private static long gcd(long a, long b) {
		if (b == 0) {
			return a;
		}
		return gcd(b, a % b);
	}

	// 複数の最大公約数を求める
	private static long gcdex(long param[]) {
		long g = gcd(param[0], param[1]);
		for (int i = 1; i < param.length-1; i++) {
			g = gcd(g, param[i+1]);
		}
		return g;
	}

	// 最小公倍数を求める
	private static long lcm(long a, long b) {
		return (a * b) / gcd(a, b);
	}

	//
	private static long all(long n, long count, int N) {
		if (count == N) {
			return count;
		}
		return all(1, count, N);
	}

} Main
import java.util.*;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		// 入力
		int N = sc.nextInt();
		int[] v = new int[N];
		for (int i = 0; i < N; i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		double ave = v[0];
		for (int i = 1; i < N; i++) {
			ave = (ave+v[i])/2;
		}
		System.out.println(ave);
	}

	// ユークリッドの控除法(最大公約数を求める)
	private static long gcd(long a, long b) {
		if (b == 0) {
			return a;
		}
		return gcd(b, a % b);
	}

	// 複数の最大公約数を求める
	private static long gcdex(long param[]) {
		long g = gcd(param[0], param[1]);
		for (int i = 1; i < param.length-1; i++) {
			g = gcd(g, param[i+1]);
		}
		return g;
	}

	// 最小公倍数を求める
	private static long lcm(long a, long b) {
		return (a * b) / gcd(a, b);
	}

	//
	private static long all(long n, long count, int N) {
		if (count == N) {
			return count;
		}
		return all(1, count, N);
	}

}