import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.NoSuchElementException;

public class Main {

	public static void main(String[] args) {
		long n = sc.nextLong();
		long[] vs = new long[(int) n];
		for (int i = 0; i < n; i++) {
			vs[i] = sc.nextLong();
		}
		Arrays.sort(vs);

		double r = vs[0];
		for (int i = 1; i < n; i++) {
			r = (r+vs[i])/2d;
		}

		pw.println(r);
		pw.flush();
	}

	double create(double x, double y) {
		return (x + y) / 2d;
	}

	static final FastScanner sc = new FastScanner();
	static final PrintWriter pw = new PrintWriter(System.out);

	static class FastScanner {
		private final InputStream in = System.in;
		private final byte[] buffer = new byte[1024];
		private int ptr = 0;
		private int buflen = 0;

		private boolean hasNextByte() {
			if (ptr < buflen) {
				return true;
			} else {
				ptr = 0;
				try {
					buflen = in.read(buffer);
				} catch (IOException e) {
					e.printStackTrace();
				}
				if (buflen <= 0) {
					return false;
				}
			}
			return true;
		}

		private int readByte() {
			if (hasNextByte())
				return buffer[ptr++];
			else
				return -1;
		}

		static boolean isPrintableChar(int c) {
			return 33 <= c && c <= 126;
		}

		private void skipUnprintable() {
			while (hasNextByte() && !isPrintableChar(buffer[ptr]))
				ptr++;
		}

		public boolean hasNext() {
			skipUnprintable();
			return hasNextByte();
		}

		public String next() {
			if (!hasNext())
				throw new NoSuchElementException();
			StringBuilder sb = new StringBuilder();
			int b = readByte();
			while (isPrintableChar(b)) {
				sb.appendCodePoint(b);
				b = readByte();
			}
			return sb.toString();
		}

		public long nextLong() {
			if (!hasNext())
				throw new NoSuchElementException();
			long n = 0;
			boolean minus = false;
			int b = readByte();
			if (b == '-') {
				minus = true;
				b = readByte();
			}
			if (b < '0' || '9' < b) {
				throw new NumberFormatException();
			}
			while (true) {
				if ('0' <= b && b <= '9') {
					n *= 10;
					n += b - '0';
				} else if (b == -1 || !isPrintableChar(b)) {
					return minus ? -n : n;
				} else {
					throw new NumberFormatException();
				}
				b = readByte();
			}
		}
	}
} import java.io.IOException; IOException java.io import java.io.InputStream; InputStream java.io import java.io.PrintWriter; PrintWriter java.io import java.util.Arrays; Arrays java.util import java.util.NoSuchElementException; NoSuchElementException java.util public class Main {

	public static void main(String[] args) {
		long n = sc.nextLong();
		long[] vs = new long[(int) n];
		for (int i = 0; i < n; i++) {
			vs[i] = sc.nextLong();
		}
		Arrays.sort(vs);

		double r = vs[0];
		for (int i = 1; i < n; i++) {
			r = (r+vs[i])/2d;
		}

		pw.println(r);
		pw.flush();
	}

	double create(double x, double y) {
		return (x + y) / 2d;
	}

	static final FastScanner sc = new FastScanner();
	static final PrintWriter pw = new PrintWriter(System.out);

	static class FastScanner {
		private final InputStream in = System.in;
		private final byte[] buffer = new byte[1024];
		private int ptr = 0;
		private int buflen = 0;

		private boolean hasNextByte() {
			if (ptr < buflen) {
				return true;
			} else {
				ptr = 0;
				try {
					buflen = in.read(buffer);
				} catch (IOException e) {
					e.printStackTrace();
				}
				if (buflen <= 0) {
					return false;
				}
			}
			return true;
		}

		private int readByte() {
			if (hasNextByte())
				return buffer[ptr++];
			else
				return -1;
		}

		static boolean isPrintableChar(int c) {
			return 33 <= c && c <= 126;
		}

		private void skipUnprintable() {
			while (hasNextByte() && !isPrintableChar(buffer[ptr]))
				ptr++;
		}

		public boolean hasNext() {
			skipUnprintable();
			return hasNextByte();
		}

		public String next() {
			if (!hasNext())
				throw new NoSuchElementException();
			StringBuilder sb = new StringBuilder();
			int b = readByte();
			while (isPrintableChar(b)) {
				sb.appendCodePoint(b);
				b = readByte();
			}
			return sb.toString();
		}

		public long nextLong() {
			if (!hasNext())
				throw new NoSuchElementException();
			long n = 0;
			boolean minus = false;
			int b = readByte();
			if (b == '-') {
				minus = true;
				b = readByte();
			}
			if (b < '0' || '9' < b) {
				throw new NumberFormatException();
			}
			while (true) {
				if ('0' <= b && b <= '9') {
					n *= 10;
					n += b - '0';
				} else if (b == -1 || !isPrintableChar(b)) {
					return minus ? -n : n;
				} else {
					throw new NumberFormatException();
				}
				b = readByte();
			}
		}
	}
} Main static final FastScanner sc = new FastScanner(); sc new FastScanner() static final PrintWriter pw = new PrintWriter(System.out); pw new PrintWriter(System.out) public static void main(String[] args) {
		long n = sc.nextLong();
		long[] vs = new long[(int) n];
		for (int i = 0; i < n; i++) {
			vs[i] = sc.nextLong();
		}
		Arrays.sort(vs);

		double r = vs[0];
		for (int i = 1; i < n; i++) {
			r = (r+vs[i])/2d;
		}

		pw.println(r);
		pw.flush();
	} main {
		long n = sc.nextLong();
		long[] vs = new long[(int) n];
		for (int i = 0; i < n; i++) {
			vs[i] = sc.nextLong();
		}
		Arrays.sort(vs);

		double r = vs[0];
		for (int i = 1; i < n; i++) {
			r = (r+vs[i])/2d;
		}

		pw.println(r);
		pw.flush();
	} long n = sc.nextLong(); n sc.nextLong() sc.nextLong sc long[] vs = new long[(int) n]; vs new long[(int) n] (int) n for (int i = 0; i < n; i++) {
			vs[i] = sc.nextLong();
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			vs[i] = sc.nextLong();
		} {
			vs[i] = sc.nextLong();
		} vs[i] = sc.nextLong() vs[i] vs i sc.nextLong() sc.nextLong sc Arrays.sort(vs) Arrays.sort Arrays vs double r = vs[0]; r vs[0] vs 0 for (int i = 1; i < n; i++) {
			r = (r+vs[i])/2d;
		} int i = 1; int i = 1; i 1 i < n i n i++ i++ i {
			r = (r+vs[i])/2d;
		} {
			r = (r+vs[i])/2d;
		} r = (r+vs[i])/2d r (r+vs[i])/2d (r+vs[i]) r vs[i] vs i 2d pw.println(r) pw.println pw r pw.flush() pw.flush pw String[] args args double create(double x, double y) {
		return (x + y) / 2d;
	} create {
		return (x + y) / 2d;
	} return (x + y) / 2d; (x + y) / 2d (x + y) x y 2d double x x double y y static class FastScanner {
		private final InputStream in = System.in;
		private final byte[] buffer = new byte[1024];
		private int ptr = 0;
		private int buflen = 0;

		private boolean hasNextByte() {
			if (ptr < buflen) {
				return true;
			} else {
				ptr = 0;
				try {
					buflen = in.read(buffer);
				} catch (IOException e) {
					e.printStackTrace();
				}
				if (buflen <= 0) {
					return false;
				}
			}
			return true;
		}

		private int readByte() {
			if (hasNextByte())
				return buffer[ptr++];
			else
				return -1;
		}

		static boolean isPrintableChar(int c) {
			return 33 <= c && c <= 126;
		}

		private void skipUnprintable() {
			while (hasNextByte() && !isPrintableChar(buffer[ptr]))
				ptr++;
		}

		public boolean hasNext() {
			skipUnprintable();
			return hasNextByte();
		}

		public String next() {
			if (!hasNext())
				throw new NoSuchElementException();
			StringBuilder sb = new StringBuilder();
			int b = readByte();
			while (isPrintableChar(b)) {
				sb.appendCodePoint(b);
				b = readByte();
			}
			return sb.toString();
		}

		public long nextLong() {
			if (!hasNext())
				throw new NoSuchElementException();
			long n = 0;
			boolean minus = false;
			int b = readByte();
			if (b == '-') {
				minus = true;
				b = readByte();
			}
			if (b < '0' || '9' < b) {
				throw new NumberFormatException();
			}
			while (true) {
				if ('0' <= b && b <= '9') {
					n *= 10;
					n += b - '0';
				} else if (b == -1 || !isPrintableChar(b)) {
					return minus ? -n : n;
				} else {
					throw new NumberFormatException();
				}
				b = readByte();
			}
		}
	} FastScanner private final InputStream in = System.in; in System.in System System.in private final byte[] buffer = new byte[1024]; buffer new byte[1024] 1024 private int ptr = 0; ptr 0 private int buflen = 0; buflen 0 private boolean hasNextByte() {
			if (ptr < buflen) {
				return true;
			} else {
				ptr = 0;
				try {
					buflen = in.read(buffer);
				} catch (IOException e) {
					e.printStackTrace();
				}
				if (buflen <= 0) {
					return false;
				}
			}
			return true;
		} hasNextByte {
			if (ptr < buflen) {
				return true;
			} else {
				ptr = 0;
				try {
					buflen = in.read(buffer);
				} catch (IOException e) {
					e.printStackTrace();
				}
				if (buflen <= 0) {
					return false;
				}
			}
			return true;
		} if (ptr < buflen) {
				return true;
			} else {
				ptr = 0;
				try {
					buflen = in.read(buffer);
				} catch (IOException e) {
					e.printStackTrace();
				}
				if (buflen <= 0) {
					return false;
				}
			} ptr < buflen ptr buflen {
				return true;
			} return true; true {
				ptr = 0;
				try {
					buflen = in.read(buffer);
				} catch (IOException e) {
					e.printStackTrace();
				}
				if (buflen <= 0) {
					return false;
				}
			} ptr = 0 ptr 0 try {
					buflen = in.read(buffer);
				} catch (IOException e) {
					e.printStackTrace();
				} catch (IOException e) {
					e.printStackTrace();
				} IOException e {
					e.printStackTrace();
				} e.printStackTrace() e.printStackTrace e {
					buflen = in.read(buffer);
				} buflen = in.read(buffer) buflen in.read(buffer) in.read in buffer if (buflen <= 0) {
					return false;
				} buflen <= 0 buflen 0 {
					return false;
				} return false; false return true; true private int readByte() {
			if (hasNextByte())
				return buffer[ptr++];
			else
				return -1;
		} readByte {
			if (hasNextByte())
				return buffer[ptr++];
			else
				return -1;
		} if (hasNextByte())
				return buffer[ptr++];
			else
				return -1; hasNextByte() hasNextByte return buffer[ptr++]; buffer[ptr++] buffer ptr++ ptr return -1; -1 1 static boolean isPrintableChar(int c) {
			return 33 <= c && c <= 126;
		} isPrintableChar {
			return 33 <= c && c <= 126;
		} return 33 <= c && c <= 126; 33 <= c && c <= 126 33 <= c 33 c c <= 126 c 126 int c c private void skipUnprintable() {
			while (hasNextByte() && !isPrintableChar(buffer[ptr]))
				ptr++;
		} skipUnprintable {
			while (hasNextByte() && !isPrintableChar(buffer[ptr]))
				ptr++;
		} while (hasNextByte() && !isPrintableChar(buffer[ptr]))
				ptr++; hasNextByte() && !isPrintableChar(buffer[ptr]) hasNextByte() hasNextByte !isPrintableChar(buffer[ptr]) isPrintableChar(buffer[ptr]) isPrintableChar buffer[ptr] buffer ptr ptr++ ptr public boolean hasNext() {
			skipUnprintable();
			return hasNextByte();
		} hasNext {
			skipUnprintable();
			return hasNextByte();
		} skipUnprintable() skipUnprintable return hasNextByte(); hasNextByte() hasNextByte public String next() {
			if (!hasNext())
				throw new NoSuchElementException();
			StringBuilder sb = new StringBuilder();
			int b = readByte();
			while (isPrintableChar(b)) {
				sb.appendCodePoint(b);
				b = readByte();
			}
			return sb.toString();
		} next {
			if (!hasNext())
				throw new NoSuchElementException();
			StringBuilder sb = new StringBuilder();
			int b = readByte();
			while (isPrintableChar(b)) {
				sb.appendCodePoint(b);
				b = readByte();
			}
			return sb.toString();
		} if (!hasNext())
				throw new NoSuchElementException(); !hasNext() hasNext() hasNext throw new NoSuchElementException(); new NoSuchElementException() StringBuilder sb = new StringBuilder(); sb new StringBuilder() int b = readByte(); b readByte() readByte while (isPrintableChar(b)) {
				sb.appendCodePoint(b);
				b = readByte();
			} isPrintableChar(b) isPrintableChar b {
				sb.appendCodePoint(b);
				b = readByte();
			} sb.appendCodePoint(b) sb.appendCodePoint sb b b = readByte() b readByte() readByte return sb.toString(); sb.toString() sb.toString sb public long nextLong() {
			if (!hasNext())
				throw new NoSuchElementException();
			long n = 0;
			boolean minus = false;
			int b = readByte();
			if (b == '-') {
				minus = true;
				b = readByte();
			}
			if (b < '0' || '9' < b) {
				throw new NumberFormatException();
			}
			while (true) {
				if ('0' <= b && b <= '9') {
					n *= 10;
					n += b - '0';
				} else if (b == -1 || !isPrintableChar(b)) {
					return minus ? -n : n;
				} else {
					throw new NumberFormatException();
				}
				b = readByte();
			}
		} nextLong {
			if (!hasNext())
				throw new NoSuchElementException();
			long n = 0;
			boolean minus = false;
			int b = readByte();
			if (b == '-') {
				minus = true;
				b = readByte();
			}
			if (b < '0' || '9' < b) {
				throw new NumberFormatException();
			}
			while (true) {
				if ('0' <= b && b <= '9') {
					n *= 10;
					n += b - '0';
				} else if (b == -1 || !isPrintableChar(b)) {
					return minus ? -n : n;
				} else {
					throw new NumberFormatException();
				}
				b = readByte();
			}
		} if (!hasNext())
				throw new NoSuchElementException(); !hasNext() hasNext() hasNext throw new NoSuchElementException(); new NoSuchElementException() long n = 0; n 0 boolean minus = false; minus false int b = readByte(); b readByte() readByte if (b == '-') {
				minus = true;
				b = readByte();
			} b == '-' b '-' {
				minus = true;
				b = readByte();
			} minus = true minus true b = readByte() b readByte() readByte if (b < '0' || '9' < b) {
				throw new NumberFormatException();
			} b < '0' || '9' < b b < '0' b '0' '9' < b '9' b {
				throw new NumberFormatException();
			} throw new NumberFormatException(); new NumberFormatException() while (true) {
				if ('0' <= b && b <= '9') {
					n *= 10;
					n += b - '0';
				} else if (b == -1 || !isPrintableChar(b)) {
					return minus ? -n : n;
				} else {
					throw new NumberFormatException();
				}
				b = readByte();
			} true {
				if ('0' <= b && b <= '9') {
					n *= 10;
					n += b - '0';
				} else if (b == -1 || !isPrintableChar(b)) {
					return minus ? -n : n;
				} else {
					throw new NumberFormatException();
				}
				b = readByte();
			} if ('0' <= b && b <= '9') {
					n *= 10;
					n += b - '0';
				} else if (b == -1 || !isPrintableChar(b)) {
					return minus ? -n : n;
				} else {
					throw new NumberFormatException();
				} '0' <= b && b <= '9' '0' <= b '0' b b <= '9' b '9' {
					n *= 10;
					n += b - '0';
				} n *= 10 n 10 n += b - '0' n b - '0' b '0' if (b == -1 || !isPrintableChar(b)) {
					return minus ? -n : n;
				} else {
					throw new NumberFormatException();
				} b == -1 || !isPrintableChar(b) b == -1 b -1 1 !isPrintableChar(b) isPrintableChar(b) isPrintableChar b {
					return minus ? -n : n;
				} return minus ? -n : n; minus ? -n : n minus -n n n {
					throw new NumberFormatException();
				} throw new NumberFormatException(); new NumberFormatException() b = readByte() b readByte() readByte public class Main {

	public static void main(String[] args) {
		long n = sc.nextLong();
		long[] vs = new long[(int) n];
		for (int i = 0; i < n; i++) {
			vs[i] = sc.nextLong();
		}
		Arrays.sort(vs);

		double r = vs[0];
		for (int i = 1; i < n; i++) {
			r = (r+vs[i])/2d;
		}

		pw.println(r);
		pw.flush();
	}

	double create(double x, double y) {
		return (x + y) / 2d;
	}

	static final FastScanner sc = new FastScanner();
	static final PrintWriter pw = new PrintWriter(System.out);

	static class FastScanner {
		private final InputStream in = System.in;
		private final byte[] buffer = new byte[1024];
		private int ptr = 0;
		private int buflen = 0;

		private boolean hasNextByte() {
			if (ptr < buflen) {
				return true;
			} else {
				ptr = 0;
				try {
					buflen = in.read(buffer);
				} catch (IOException e) {
					e.printStackTrace();
				}
				if (buflen <= 0) {
					return false;
				}
			}
			return true;
		}

		private int readByte() {
			if (hasNextByte())
				return buffer[ptr++];
			else
				return -1;
		}

		static boolean isPrintableChar(int c) {
			return 33 <= c && c <= 126;
		}

		private void skipUnprintable() {
			while (hasNextByte() && !isPrintableChar(buffer[ptr]))
				ptr++;
		}

		public boolean hasNext() {
			skipUnprintable();
			return hasNextByte();
		}

		public String next() {
			if (!hasNext())
				throw new NoSuchElementException();
			StringBuilder sb = new StringBuilder();
			int b = readByte();
			while (isPrintableChar(b)) {
				sb.appendCodePoint(b);
				b = readByte();
			}
			return sb.toString();
		}

		public long nextLong() {
			if (!hasNext())
				throw new NoSuchElementException();
			long n = 0;
			boolean minus = false;
			int b = readByte();
			if (b == '-') {
				minus = true;
				b = readByte();
			}
			if (b < '0' || '9' < b) {
				throw new NumberFormatException();
			}
			while (true) {
				if ('0' <= b && b <= '9') {
					n *= 10;
					n += b - '0';
				} else if (b == -1 || !isPrintableChar(b)) {
					return minus ? -n : n;
				} else {
					throw new NumberFormatException();
				}
				b = readByte();
			}
		}
	}
} public class Main {

	public static void main(String[] args) {
		long n = sc.nextLong();
		long[] vs = new long[(int) n];
		for (int i = 0; i < n; i++) {
			vs[i] = sc.nextLong();
		}
		Arrays.sort(vs);

		double r = vs[0];
		for (int i = 1; i < n; i++) {
			r = (r+vs[i])/2d;
		}

		pw.println(r);
		pw.flush();
	}

	double create(double x, double y) {
		return (x + y) / 2d;
	}

	static final FastScanner sc = new FastScanner();
	static final PrintWriter pw = new PrintWriter(System.out);

	static class FastScanner {
		private final InputStream in = System.in;
		private final byte[] buffer = new byte[1024];
		private int ptr = 0;
		private int buflen = 0;

		private boolean hasNextByte() {
			if (ptr < buflen) {
				return true;
			} else {
				ptr = 0;
				try {
					buflen = in.read(buffer);
				} catch (IOException e) {
					e.printStackTrace();
				}
				if (buflen <= 0) {
					return false;
				}
			}
			return true;
		}

		private int readByte() {
			if (hasNextByte())
				return buffer[ptr++];
			else
				return -1;
		}

		static boolean isPrintableChar(int c) {
			return 33 <= c && c <= 126;
		}

		private void skipUnprintable() {
			while (hasNextByte() && !isPrintableChar(buffer[ptr]))
				ptr++;
		}

		public boolean hasNext() {
			skipUnprintable();
			return hasNextByte();
		}

		public String next() {
			if (!hasNext())
				throw new NoSuchElementException();
			StringBuilder sb = new StringBuilder();
			int b = readByte();
			while (isPrintableChar(b)) {
				sb.appendCodePoint(b);
				b = readByte();
			}
			return sb.toString();
		}

		public long nextLong() {
			if (!hasNext())
				throw new NoSuchElementException();
			long n = 0;
			boolean minus = false;
			int b = readByte();
			if (b == '-') {
				minus = true;
				b = readByte();
			}
			if (b < '0' || '9' < b) {
				throw new NumberFormatException();
			}
			while (true) {
				if ('0' <= b && b <= '9') {
					n *= 10;
					n += b - '0';
				} else if (b == -1 || !isPrintableChar(b)) {
					return minus ? -n : n;
				} else {
					throw new NumberFormatException();
				}
				b = readByte();
			}
		}
	}
} Main
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.NoSuchElementException;

public class Main {

	public static void main(String[] args) {
		long n = sc.nextLong();
		long[] vs = new long[(int) n];
		for (int i = 0; i < n; i++) {
			vs[i] = sc.nextLong();
		}
		Arrays.sort(vs);

		double r = vs[0];
		for (int i = 1; i < n; i++) {
			r = (r+vs[i])/2d;
		}

		pw.println(r);
		pw.flush();
	}

	double create(double x, double y) {
		return (x + y) / 2d;
	}

	static final FastScanner sc = new FastScanner();
	static final PrintWriter pw = new PrintWriter(System.out);

	static class FastScanner {
		private final InputStream in = System.in;
		private final byte[] buffer = new byte[1024];
		private int ptr = 0;
		private int buflen = 0;

		private boolean hasNextByte() {
			if (ptr < buflen) {
				return true;
			} else {
				ptr = 0;
				try {
					buflen = in.read(buffer);
				} catch (IOException e) {
					e.printStackTrace();
				}
				if (buflen <= 0) {
					return false;
				}
			}
			return true;
		}

		private int readByte() {
			if (hasNextByte())
				return buffer[ptr++];
			else
				return -1;
		}

		static boolean isPrintableChar(int c) {
			return 33 <= c && c <= 126;
		}

		private void skipUnprintable() {
			while (hasNextByte() && !isPrintableChar(buffer[ptr]))
				ptr++;
		}

		public boolean hasNext() {
			skipUnprintable();
			return hasNextByte();
		}

		public String next() {
			if (!hasNext())
				throw new NoSuchElementException();
			StringBuilder sb = new StringBuilder();
			int b = readByte();
			while (isPrintableChar(b)) {
				sb.appendCodePoint(b);
				b = readByte();
			}
			return sb.toString();
		}

		public long nextLong() {
			if (!hasNext())
				throw new NoSuchElementException();
			long n = 0;
			boolean minus = false;
			int b = readByte();
			if (b == '-') {
				minus = true;
				b = readByte();
			}
			if (b < '0' || '9' < b) {
				throw new NumberFormatException();
			}
			while (true) {
				if ('0' <= b && b <= '9') {
					n *= 10;
					n += b - '0';
				} else if (b == -1 || !isPrintableChar(b)) {
					return minus ? -n : n;
				} else {
					throw new NumberFormatException();
				}
				b = readByte();
			}
		}
	}
}
