import java.util.*;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		float v[] = new float[n];
		for(int i = 0; i < n; i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		
		float ans = v[0];

		for(int i = 0; i < n; i++) {
			ans = (ans + v[i]) / 2;
//			System.out.println(ans);
		}
		
		System.out.println(ans);
	}
} import java.util.*; util.* java public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		float v[] = new float[n];
		for(int i = 0; i < n; i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		
		float ans = v[0];

		for(int i = 0; i < n; i++) {
			ans = (ans + v[i]) / 2;
//			System.out.println(ans);
		}
		
		System.out.println(ans);
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		float v[] = new float[n];
		for(int i = 0; i < n; i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		
		float ans = v[0];

		for(int i = 0; i < n; i++) {
			ans = (ans + v[i]) / 2;
//			System.out.println(ans);
		}
		
		System.out.println(ans);
	} main {
		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		float v[] = new float[n];
		for(int i = 0; i < n; i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		
		float ans = v[0];

		for(int i = 0; i < n; i++) {
			ans = (ans + v[i]) / 2;
//			System.out.println(ans);
		}
		
		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 float v[] = new float[n]; v new float[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 float ans = v[0]; ans v[0] v 0 for(int i = 0; i < n; i++) {
			ans = (ans + v[i]) / 2;
//			System.out.println(ans);
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			ans = (ans + v[i]) / 2;
//			System.out.println(ans);
		} {
			ans = (ans + v[i]) / 2;
//			System.out.println(ans);
		} ans = (ans + v[i]) / 2 ans (ans + v[i]) / 2 (ans + v[i]) ans v[i] v 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) {
		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		float v[] = new float[n];
		for(int i = 0; i < n; i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		
		float ans = v[0];

		for(int i = 0; i < n; i++) {
			ans = (ans + v[i]) / 2;
//			System.out.println(ans);
		}
		
		System.out.println(ans);
	}
} public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		float v[] = new float[n];
		for(int i = 0; i < n; i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		
		float ans = v[0];

		for(int i = 0; i < n; i++) {
			ans = (ans + v[i]) / 2;
//			System.out.println(ans);
		}
		
		System.out.println(ans);
	}
} Main
import java.util.*;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		int n = sc.nextInt();
		float v[] = new float[n];
		for(int i = 0; i < n; i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		
		float ans = v[0];

		for(int i = 0; i < n; i++) {
			ans = (ans + v[i]) / 2;
//			System.out.println(ans);
		}
		
		System.out.println(ans);
	}
}