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

public class Main {
	public static void main(String[] args) {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		int n = 0;
		try {
			n = Integer.parseInt(br.readLine());
		} catch (IOException e) {
			e.getStackTrace();
		}
		
		double v[] = new double [n];
		String str[] = new String [n];
		String line;
		try {
			line = br.readLine();
			str = line.split(" ");
			for (int i = 0; i < n; i++) {
				v[i] = Integer.parseInt(str[i]);
			}
		} catch (IOException e) {
			e.getStackTrace();
		}
		
		Arrays.sort(v);
		
		for(int i = 0; i < n - 1; i++) {
			v[i+1] = (v[i] + v[i+1]) / 2.0;
		}
		
		System.out.println(v[n-1]);
		
	}
} import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException 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) {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		int n = 0;
		try {
			n = Integer.parseInt(br.readLine());
		} catch (IOException e) {
			e.getStackTrace();
		}
		
		double v[] = new double [n];
		String str[] = new String [n];
		String line;
		try {
			line = br.readLine();
			str = line.split(" ");
			for (int i = 0; i < n; i++) {
				v[i] = Integer.parseInt(str[i]);
			}
		} catch (IOException e) {
			e.getStackTrace();
		}
		
		Arrays.sort(v);
		
		for(int i = 0; i < n - 1; i++) {
			v[i+1] = (v[i] + v[i+1]) / 2.0;
		}
		
		System.out.println(v[n-1]);
		
	}
} Main public static void main(String[] args) {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		int n = 0;
		try {
			n = Integer.parseInt(br.readLine());
		} catch (IOException e) {
			e.getStackTrace();
		}
		
		double v[] = new double [n];
		String str[] = new String [n];
		String line;
		try {
			line = br.readLine();
			str = line.split(" ");
			for (int i = 0; i < n; i++) {
				v[i] = Integer.parseInt(str[i]);
			}
		} catch (IOException e) {
			e.getStackTrace();
		}
		
		Arrays.sort(v);
		
		for(int i = 0; i < n - 1; i++) {
			v[i+1] = (v[i] + v[i+1]) / 2.0;
		}
		
		System.out.println(v[n-1]);
		
	} main {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		int n = 0;
		try {
			n = Integer.parseInt(br.readLine());
		} catch (IOException e) {
			e.getStackTrace();
		}
		
		double v[] = new double [n];
		String str[] = new String [n];
		String line;
		try {
			line = br.readLine();
			str = line.split(" ");
			for (int i = 0; i < n; i++) {
				v[i] = Integer.parseInt(str[i]);
			}
		} catch (IOException e) {
			e.getStackTrace();
		}
		
		Arrays.sort(v);
		
		for(int i = 0; i < n - 1; i++) {
			v[i+1] = (v[i] + v[i+1]) / 2.0;
		}
		
		System.out.println(v[n-1]);
		
	} BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); br new BufferedReader(new InputStreamReader(System.in)) int n = 0; n 0 try {
			n = Integer.parseInt(br.readLine());
		} catch (IOException e) {
			e.getStackTrace();
		} catch (IOException e) {
			e.getStackTrace();
		} IOException e {
			e.getStackTrace();
		} e.getStackTrace() e.getStackTrace e {
			n = Integer.parseInt(br.readLine());
		} n = Integer.parseInt(br.readLine()) n Integer.parseInt(br.readLine()) Integer.parseInt Integer br.readLine() br.readLine br double v[] = new double [n]; v new double [n] n String str[] = new String [n]; str new String [n] n String line; line try {
			line = br.readLine();
			str = line.split(" ");
			for (int i = 0; i < n; i++) {
				v[i] = Integer.parseInt(str[i]);
			}
		} catch (IOException e) {
			e.getStackTrace();
		} catch (IOException e) {
			e.getStackTrace();
		} IOException e {
			e.getStackTrace();
		} e.getStackTrace() e.getStackTrace e {
			line = br.readLine();
			str = line.split(" ");
			for (int i = 0; i < n; i++) {
				v[i] = Integer.parseInt(str[i]);
			}
		} line = br.readLine() line br.readLine() br.readLine br str = line.split(" ") str line.split(" ") line.split line " " for (int i = 0; i < n; i++) {
				v[i] = Integer.parseInt(str[i]);
			} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
				v[i] = Integer.parseInt(str[i]);
			} {
				v[i] = Integer.parseInt(str[i]);
			} v[i] = Integer.parseInt(str[i]) v[i] v i Integer.parseInt(str[i]) Integer.parseInt Integer str[i] str i Arrays.sort(v) Arrays.sort Arrays v for(int i = 0; i < n - 1; i++) {
			v[i+1] = (v[i] + v[i+1]) / 2.0;
		} int i = 0; int i = 0; i 0 i < n - 1 i n - 1 n 1 i++ i++ i {
			v[i+1] = (v[i] + v[i+1]) / 2.0;
		} {
			v[i+1] = (v[i] + v[i+1]) / 2.0;
		} v[i+1] = (v[i] + v[i+1]) / 2.0 v[i+1] v i+1 i 1 (v[i] + v[i+1]) / 2.0 (v[i] + v[i+1]) v[i] v i v[i+1] v i+1 i 1 2.0 System.out.println(v[n-1]) System.out.println System.out System System.out v[n-1] v n-1 n 1 String[] args args public class Main {
	public static void main(String[] args) {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		int n = 0;
		try {
			n = Integer.parseInt(br.readLine());
		} catch (IOException e) {
			e.getStackTrace();
		}
		
		double v[] = new double [n];
		String str[] = new String [n];
		String line;
		try {
			line = br.readLine();
			str = line.split(" ");
			for (int i = 0; i < n; i++) {
				v[i] = Integer.parseInt(str[i]);
			}
		} catch (IOException e) {
			e.getStackTrace();
		}
		
		Arrays.sort(v);
		
		for(int i = 0; i < n - 1; i++) {
			v[i+1] = (v[i] + v[i+1]) / 2.0;
		}
		
		System.out.println(v[n-1]);
		
	}
} public class Main {
	public static void main(String[] args) {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		int n = 0;
		try {
			n = Integer.parseInt(br.readLine());
		} catch (IOException e) {
			e.getStackTrace();
		}
		
		double v[] = new double [n];
		String str[] = new String [n];
		String line;
		try {
			line = br.readLine();
			str = line.split(" ");
			for (int i = 0; i < n; i++) {
				v[i] = Integer.parseInt(str[i]);
			}
		} catch (IOException e) {
			e.getStackTrace();
		}
		
		Arrays.sort(v);
		
		for(int i = 0; i < n - 1; i++) {
			v[i+1] = (v[i] + v[i+1]) / 2.0;
		}
		
		System.out.println(v[n-1]);
		
	}
} Main
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Arrays;

public class Main {
	public static void main(String[] args) {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		int n = 0;
		try {
			n = Integer.parseInt(br.readLine());
		} catch (IOException e) {
			e.getStackTrace();
		}
		
		double v[] = new double [n];
		String str[] = new String [n];
		String line;
		try {
			line = br.readLine();
			str = line.split(" ");
			for (int i = 0; i < n; i++) {
				v[i] = Integer.parseInt(str[i]);
			}
		} catch (IOException e) {
			e.getStackTrace();
		}
		
		Arrays.sort(v);
		
		for(int i = 0; i < n - 1; i++) {
			v[i+1] = (v[i] + v[i+1]) / 2.0;
		}
		
		System.out.println(v[n-1]);
		
	}
}