import java.util.*;

@SuppressWarnings("unchecked")
public class Main {
	// public static void printArray(int[] a) {
	// 	for (int i = 0; i < a.length; i++) {
	// 		System.out.print(a[i] + ", ");
	// 	}
	// 	System.out.println();
	// }

	// public static<T> void printArrayT(T[] a) {
	// 	for (int i = 0; i < a.length; i++) {
	// 		System.out.print(a[i] + ", ");
	// 	}
	// 	System.out.println();
	// }

	public static String joinInt(int[] a, String separator) {
		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < a.length; i++) {
			if (i > 0) {
				sb.append(separator);
			}
			sb.append(a[i]);
		}
		return sb.toString();		
	}

	static int[] nextIntArray(Scanner sc, int N) {
		int[] arr = new int[N];
		for (int i = 0; i < N; i++) {
			arr[i] = sc.nextInt();
		}
		return arr;
	}

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int[] v = new int[N];
		for (int i = 0; i < N; i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		double x = v[0];
		for (int i = 1; i < N; i++) {
			x = (x + v[i])/2;
		}
		System.out.println(x);
	}
} import java.util.*; util.* java public class Main {
	// public static void printArray(int[] a) {
	// 	for (int i = 0; i < a.length; i++) {
	// 		System.out.print(a[i] + ", ");
	// 	}
	// 	System.out.println();
	// }

	// public static<T> void printArrayT(T[] a) {
	// 	for (int i = 0; i < a.length; i++) {
	// 		System.out.print(a[i] + ", ");
	// 	}
	// 	System.out.println();
	// }

	public static String joinInt(int[] a, String separator) {
		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < a.length; i++) {
			if (i > 0) {
				sb.append(separator);
			}
			sb.append(a[i]);
		}
		return sb.toString();		
	}

	static int[] nextIntArray(Scanner sc, int N) {
		int[] arr = new int[N];
		for (int i = 0; i < N; i++) {
			arr[i] = sc.nextInt();
		}
		return arr;
	}

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int[] v = new int[N];
		for (int i = 0; i < N; i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		double x = v[0];
		for (int i = 1; i < N; i++) {
			x = (x + v[i])/2;
		}
		System.out.println(x);
	}
} Main public static String joinInt(int[] a, String separator) {
		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < a.length; i++) {
			if (i > 0) {
				sb.append(separator);
			}
			sb.append(a[i]);
		}
		return sb.toString();		
	} joinInt {
		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < a.length; i++) {
			if (i > 0) {
				sb.append(separator);
			}
			sb.append(a[i]);
		}
		return sb.toString();		
	} StringBuilder sb = new StringBuilder(); sb new StringBuilder() for (int i = 0; i < a.length; i++) {
			if (i > 0) {
				sb.append(separator);
			}
			sb.append(a[i]);
		} int i = 0; int i = 0; i 0 i < a.length i a.length a a.length i++ i++ i {
			if (i > 0) {
				sb.append(separator);
			}
			sb.append(a[i]);
		} {
			if (i > 0) {
				sb.append(separator);
			}
			sb.append(a[i]);
		} if (i > 0) {
				sb.append(separator);
			} i > 0 i 0 {
				sb.append(separator);
			} sb.append(separator) sb.append sb separator sb.append(a[i]) sb.append sb a[i] a i return sb.toString(); sb.toString() sb.toString sb int[] a a String separator separator static int[] nextIntArray(Scanner sc, int N) {
		int[] arr = new int[N];
		for (int i = 0; i < N; i++) {
			arr[i] = sc.nextInt();
		}
		return arr;
	} nextIntArray {
		int[] arr = new int[N];
		for (int i = 0; i < N; i++) {
			arr[i] = sc.nextInt();
		}
		return arr;
	} int[] arr = new int[N]; arr new int[N] N for (int i = 0; i < N; i++) {
			arr[i] = sc.nextInt();
		} int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
			arr[i] = sc.nextInt();
		} {
			arr[i] = sc.nextInt();
		} arr[i] = sc.nextInt() arr[i] arr i sc.nextInt() sc.nextInt sc return arr; arr Scanner sc sc int N N public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int[] v = new int[N];
		for (int i = 0; i < N; i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		double x = v[0];
		for (int i = 1; i < N; i++) {
			x = (x + v[i])/2;
		}
		System.out.println(x);
	} main {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int[] v = new int[N];
		for (int i = 0; i < N; i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		double x = v[0];
		for (int i = 1; i < N; i++) {
			x = (x + v[i])/2;
		}
		System.out.println(x);
	} 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 x = v[0]; x v[0] v 0 for (int i = 1; i < N; i++) {
			x = (x + v[i])/2;
		} int i = 1; int i = 1; i 1 i < N i N i++ i++ i {
			x = (x + v[i])/2;
		} {
			x = (x + v[i])/2;
		} x = (x + v[i])/2 x (x + v[i])/2 (x + v[i]) x v[i] v i 2 System.out.println(x) System.out.println System.out System System.out x String[] args args public class Main {
	// public static void printArray(int[] a) {
	// 	for (int i = 0; i < a.length; i++) {
	// 		System.out.print(a[i] + ", ");
	// 	}
	// 	System.out.println();
	// }

	// public static<T> void printArrayT(T[] a) {
	// 	for (int i = 0; i < a.length; i++) {
	// 		System.out.print(a[i] + ", ");
	// 	}
	// 	System.out.println();
	// }

	public static String joinInt(int[] a, String separator) {
		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < a.length; i++) {
			if (i > 0) {
				sb.append(separator);
			}
			sb.append(a[i]);
		}
		return sb.toString();		
	}

	static int[] nextIntArray(Scanner sc, int N) {
		int[] arr = new int[N];
		for (int i = 0; i < N; i++) {
			arr[i] = sc.nextInt();
		}
		return arr;
	}

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int[] v = new int[N];
		for (int i = 0; i < N; i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		double x = v[0];
		for (int i = 1; i < N; i++) {
			x = (x + v[i])/2;
		}
		System.out.println(x);
	}
} public class Main {
	// public static void printArray(int[] a) {
	// 	for (int i = 0; i < a.length; i++) {
	// 		System.out.print(a[i] + ", ");
	// 	}
	// 	System.out.println();
	// }

	// public static<T> void printArrayT(T[] a) {
	// 	for (int i = 0; i < a.length; i++) {
	// 		System.out.print(a[i] + ", ");
	// 	}
	// 	System.out.println();
	// }

	public static String joinInt(int[] a, String separator) {
		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < a.length; i++) {
			if (i > 0) {
				sb.append(separator);
			}
			sb.append(a[i]);
		}
		return sb.toString();		
	}

	static int[] nextIntArray(Scanner sc, int N) {
		int[] arr = new int[N];
		for (int i = 0; i < N; i++) {
			arr[i] = sc.nextInt();
		}
		return arr;
	}

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int[] v = new int[N];
		for (int i = 0; i < N; i++) {
			v[i] = sc.nextInt();
		}
		Arrays.sort(v);
		double x = v[0];
		for (int i = 1; i < N; i++) {
			x = (x + v[i])/2;
		}
		System.out.println(x);
	}
} Main
import java.util.*;

@SuppressWarnings("unchecked")
public class Main {
	// public static void printArray(int[] a) {
	// 	for (int i = 0; i < a.length; i++) {
	// 		System.out.print(a[i] + ", ");
	// 	}
	// 	System.out.println();
	// }

	// public static<T> void printArrayT(T[] a) {
	// 	for (int i = 0; i < a.length; i++) {
	// 		System.out.print(a[i] + ", ");
	// 	}
	// 	System.out.println();
	// }

	public static String joinInt(int[] a, String separator) {
		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < a.length; i++) {
			if (i > 0) {
				sb.append(separator);
			}
			sb.append(a[i]);
		}
		return sb.toString();		
	}

	static int[] nextIntArray(Scanner sc, int N) {
		int[] arr = new int[N];
		for (int i = 0; i < N; i++) {
			arr[i] = sc.nextInt();
		}
		return arr;
	}

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