import java.math.BigDecimal;
import java.util.Arrays;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		try (Scanner sc = new Scanner(System.in)) {
			int size = sc.nextInt();
			int[] array = new int[size];
			for (int i = 0; i < size; i++) {
				array[i] = sc.nextInt();
			}
			Arrays.sort(array);
			BigDecimal ans = BigDecimal.ZERO;
			for (int i = 1; i <= size; i++) {
				BigDecimal div;
				if (i == size) {
					div = new BigDecimal(Math.pow(2, i - 1));
				} else {
					div = new BigDecimal(Math.pow(2, i));
				}
				ans = ans.add(new BigDecimal(array[size - i]).divide(div).setScale(10, BigDecimal.ROUND_HALF_UP));
			}
			System.out.println(ans);
		}
	}
} import java.math.BigDecimal; BigDecimal java.math import java.util.Arrays; Arrays java.util import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) {
		try (Scanner sc = new Scanner(System.in)) {
			int size = sc.nextInt();
			int[] array = new int[size];
			for (int i = 0; i < size; i++) {
				array[i] = sc.nextInt();
			}
			Arrays.sort(array);
			BigDecimal ans = BigDecimal.ZERO;
			for (int i = 1; i <= size; i++) {
				BigDecimal div;
				if (i == size) {
					div = new BigDecimal(Math.pow(2, i - 1));
				} else {
					div = new BigDecimal(Math.pow(2, i));
				}
				ans = ans.add(new BigDecimal(array[size - i]).divide(div).setScale(10, BigDecimal.ROUND_HALF_UP));
			}
			System.out.println(ans);
		}
	}
} Main public static void main(String[] args) {
		try (Scanner sc = new Scanner(System.in)) {
			int size = sc.nextInt();
			int[] array = new int[size];
			for (int i = 0; i < size; i++) {
				array[i] = sc.nextInt();
			}
			Arrays.sort(array);
			BigDecimal ans = BigDecimal.ZERO;
			for (int i = 1; i <= size; i++) {
				BigDecimal div;
				if (i == size) {
					div = new BigDecimal(Math.pow(2, i - 1));
				} else {
					div = new BigDecimal(Math.pow(2, i));
				}
				ans = ans.add(new BigDecimal(array[size - i]).divide(div).setScale(10, BigDecimal.ROUND_HALF_UP));
			}
			System.out.println(ans);
		}
	} main {
		try (Scanner sc = new Scanner(System.in)) {
			int size = sc.nextInt();
			int[] array = new int[size];
			for (int i = 0; i < size; i++) {
				array[i] = sc.nextInt();
			}
			Arrays.sort(array);
			BigDecimal ans = BigDecimal.ZERO;
			for (int i = 1; i <= size; i++) {
				BigDecimal div;
				if (i == size) {
					div = new BigDecimal(Math.pow(2, i - 1));
				} else {
					div = new BigDecimal(Math.pow(2, i));
				}
				ans = ans.add(new BigDecimal(array[size - i]).divide(div).setScale(10, BigDecimal.ROUND_HALF_UP));
			}
			System.out.println(ans);
		}
	} try (Scanner sc = new Scanner(System.in)) {
			int size = sc.nextInt();
			int[] array = new int[size];
			for (int i = 0; i < size; i++) {
				array[i] = sc.nextInt();
			}
			Arrays.sort(array);
			BigDecimal ans = BigDecimal.ZERO;
			for (int i = 1; i <= size; i++) {
				BigDecimal div;
				if (i == size) {
					div = new BigDecimal(Math.pow(2, i - 1));
				} else {
					div = new BigDecimal(Math.pow(2, i));
				}
				ans = ans.add(new BigDecimal(array[size - i]).divide(div).setScale(10, BigDecimal.ROUND_HALF_UP));
			}
			System.out.println(ans);
		} {
			int size = sc.nextInt();
			int[] array = new int[size];
			for (int i = 0; i < size; i++) {
				array[i] = sc.nextInt();
			}
			Arrays.sort(array);
			BigDecimal ans = BigDecimal.ZERO;
			for (int i = 1; i <= size; i++) {
				BigDecimal div;
				if (i == size) {
					div = new BigDecimal(Math.pow(2, i - 1));
				} else {
					div = new BigDecimal(Math.pow(2, i));
				}
				ans = ans.add(new BigDecimal(array[size - i]).divide(div).setScale(10, BigDecimal.ROUND_HALF_UP));
			}
			System.out.println(ans);
		} Scanner sc = new Scanner(System.in) Scanner sc = new Scanner(System.in) new Scanner(System.in) int size = sc.nextInt(); size sc.nextInt() sc.nextInt sc int[] array = new int[size]; array new int[size] size for (int i = 0; i < size; i++) {
				array[i] = sc.nextInt();
			} int i = 0; int i = 0; i 0 i < size i size i++ i++ i {
				array[i] = sc.nextInt();
			} {
				array[i] = sc.nextInt();
			} array[i] = sc.nextInt() array[i] array i sc.nextInt() sc.nextInt sc Arrays.sort(array) Arrays.sort Arrays array BigDecimal ans = BigDecimal.ZERO; ans BigDecimal.ZERO BigDecimal BigDecimal.ZERO for (int i = 1; i <= size; i++) {
				BigDecimal div;
				if (i == size) {
					div = new BigDecimal(Math.pow(2, i - 1));
				} else {
					div = new BigDecimal(Math.pow(2, i));
				}
				ans = ans.add(new BigDecimal(array[size - i]).divide(div).setScale(10, BigDecimal.ROUND_HALF_UP));
			} int i = 1; int i = 1; i 1 i <= size i size i++ i++ i {
				BigDecimal div;
				if (i == size) {
					div = new BigDecimal(Math.pow(2, i - 1));
				} else {
					div = new BigDecimal(Math.pow(2, i));
				}
				ans = ans.add(new BigDecimal(array[size - i]).divide(div).setScale(10, BigDecimal.ROUND_HALF_UP));
			} {
				BigDecimal div;
				if (i == size) {
					div = new BigDecimal(Math.pow(2, i - 1));
				} else {
					div = new BigDecimal(Math.pow(2, i));
				}
				ans = ans.add(new BigDecimal(array[size - i]).divide(div).setScale(10, BigDecimal.ROUND_HALF_UP));
			} BigDecimal div; div if (i == size) {
					div = new BigDecimal(Math.pow(2, i - 1));
				} else {
					div = new BigDecimal(Math.pow(2, i));
				} i == size i size {
					div = new BigDecimal(Math.pow(2, i - 1));
				} div = new BigDecimal(Math.pow(2, i - 1)) div new BigDecimal(Math.pow(2, i - 1)) {
					div = new BigDecimal(Math.pow(2, i));
				} div = new BigDecimal(Math.pow(2, i)) div new BigDecimal(Math.pow(2, i)) ans = ans.add(new BigDecimal(array[size - i]).divide(div).setScale(10, BigDecimal.ROUND_HALF_UP)) ans ans.add(new BigDecimal(array[size - i]).divide(div).setScale(10, BigDecimal.ROUND_HALF_UP)) ans.add ans new BigDecimal(array[size - i]).divide(div).setScale(10, BigDecimal.ROUND_HALF_UP) new BigDecimal(array[size - i]).divide(div).setScale new BigDecimal(array[size - i]).divide(div) new BigDecimal(array[size - i]).divide new BigDecimal(array[size - i]) div 10 BigDecimal.ROUND_HALF_UP BigDecimal BigDecimal.ROUND_HALF_UP 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) {
		try (Scanner sc = new Scanner(System.in)) {
			int size = sc.nextInt();
			int[] array = new int[size];
			for (int i = 0; i < size; i++) {
				array[i] = sc.nextInt();
			}
			Arrays.sort(array);
			BigDecimal ans = BigDecimal.ZERO;
			for (int i = 1; i <= size; i++) {
				BigDecimal div;
				if (i == size) {
					div = new BigDecimal(Math.pow(2, i - 1));
				} else {
					div = new BigDecimal(Math.pow(2, i));
				}
				ans = ans.add(new BigDecimal(array[size - i]).divide(div).setScale(10, BigDecimal.ROUND_HALF_UP));
			}
			System.out.println(ans);
		}
	}
} public class Main {
	public static void main(String[] args) {
		try (Scanner sc = new Scanner(System.in)) {
			int size = sc.nextInt();
			int[] array = new int[size];
			for (int i = 0; i < size; i++) {
				array[i] = sc.nextInt();
			}
			Arrays.sort(array);
			BigDecimal ans = BigDecimal.ZERO;
			for (int i = 1; i <= size; i++) {
				BigDecimal div;
				if (i == size) {
					div = new BigDecimal(Math.pow(2, i - 1));
				} else {
					div = new BigDecimal(Math.pow(2, i));
				}
				ans = ans.add(new BigDecimal(array[size - i]).divide(div).setScale(10, BigDecimal.ROUND_HALF_UP));
			}
			System.out.println(ans);
		}
	}
} Main
import java.math.BigDecimal;
import java.util.Arrays;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		try (Scanner sc = new Scanner(System.in)) {
			int size = sc.nextInt();
			int[] array = new int[size];
			for (int i = 0; i < size; i++) {
				array[i] = sc.nextInt();
			}
			Arrays.sort(array);
			BigDecimal ans = BigDecimal.ZERO;
			for (int i = 1; i <= size; i++) {
				BigDecimal div;
				if (i == size) {
					div = new BigDecimal(Math.pow(2, i - 1));
				} else {
					div = new BigDecimal(Math.pow(2, i));
				}
				ans = ans.add(new BigDecimal(array[size - i]).divide(div).setScale(10, BigDecimal.ROUND_HALF_UP));
			}
			System.out.println(ans);
		}
	}
}
