

import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.util.*;


public class Main {
	
	public static class FastReader {
		BufferedReader br;
		StringTokenizer st;
	

		public FastReader() {
			br = new BufferedReader(new InputStreamReader(System.in));
		}

		String next() {
			while (st == null || !st.hasMoreTokens()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (Exception r) {
					r.printStackTrace();
				}
			}
			return st.nextToken();
		}

		int nextInt() {
			return Integer.parseInt(next());//converts string to integer
		}

		double nextDouble() {
			return Double.parseDouble(next());
		}

		long nextLong() {
			return Long.parseLong(next());
		}

		String nextLine() {
			String str = "";
			try {
				str = br.readLine();
			} catch (Exception r) {
				r.printStackTrace();
			}
			return str;
		}
	}
	
	public static PrintWriter out = new PrintWriter (new BufferedOutputStream(System.out));
    public static long mod = (long) (1e9+7);
    public final static int MAX = (int)1e5;
  // static Scanner sc = new Scanner(System.in);
   static List<Integer>[] edge;
	public static void main(String[] args) {
	   
	 FastReader sc = new FastReader();
	int n = sc.nextInt();
	Double[] r = new Double[n];
	for(int i=0;i<n;++i) r[i] = sc.nextDouble();
	Arrays.sort(r);
	double ans = r[0];
	for(int i=1;i<n;++i) {
		ans = (ans+r[i])/2; 
	}
	out.print(ans);
		out.close();
	}
	
	
} import java.io.BufferedOutputStream; BufferedOutputStream java.io import java.io.BufferedReader; BufferedReader java.io import java.io.InputStreamReader; InputStreamReader java.io import java.io.PrintWriter; PrintWriter java.io import java.math.BigInteger; BigInteger java.math import java.util.*; util.* java public class Main {
	
	public static class FastReader {
		BufferedReader br;
		StringTokenizer st;
	

		public FastReader() {
			br = new BufferedReader(new InputStreamReader(System.in));
		}

		String next() {
			while (st == null || !st.hasMoreTokens()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (Exception r) {
					r.printStackTrace();
				}
			}
			return st.nextToken();
		}

		int nextInt() {
			return Integer.parseInt(next());//converts string to integer
		}

		double nextDouble() {
			return Double.parseDouble(next());
		}

		long nextLong() {
			return Long.parseLong(next());
		}

		String nextLine() {
			String str = "";
			try {
				str = br.readLine();
			} catch (Exception r) {
				r.printStackTrace();
			}
			return str;
		}
	}
	
	public static PrintWriter out = new PrintWriter (new BufferedOutputStream(System.out));
    public static long mod = (long) (1e9+7);
    public final static int MAX = (int)1e5;
  // static Scanner sc = new Scanner(System.in);
   static List<Integer>[] edge;
	public static void main(String[] args) {
	   
	 FastReader sc = new FastReader();
	int n = sc.nextInt();
	Double[] r = new Double[n];
	for(int i=0;i<n;++i) r[i] = sc.nextDouble();
	Arrays.sort(r);
	double ans = r[0];
	for(int i=1;i<n;++i) {
		ans = (ans+r[i])/2; 
	}
	out.print(ans);
		out.close();
	}
	
	
} Main public static PrintWriter out = new PrintWriter (new BufferedOutputStream(System.out)); out new PrintWriter (new BufferedOutputStream(System.out)) public static long mod = (long) (1e9+7); mod (long) (1e9+7) 1e9 7 public final static int MAX = (int)1e5; MAX (int)1e5 // static Scanner sc = new Scanner(System.in);
   static List<Integer>[] edge; edge public static void main(String[] args) {
	   
	 FastReader sc = new FastReader();
	int n = sc.nextInt();
	Double[] r = new Double[n];
	for(int i=0;i<n;++i) r[i] = sc.nextDouble();
	Arrays.sort(r);
	double ans = r[0];
	for(int i=1;i<n;++i) {
		ans = (ans+r[i])/2; 
	}
	out.print(ans);
		out.close();
	} main {
	   
	 FastReader sc = new FastReader();
	int n = sc.nextInt();
	Double[] r = new Double[n];
	for(int i=0;i<n;++i) r[i] = sc.nextDouble();
	Arrays.sort(r);
	double ans = r[0];
	for(int i=1;i<n;++i) {
		ans = (ans+r[i])/2; 
	}
	out.print(ans);
		out.close();
	} FastReader sc = new FastReader(); sc new FastReader() int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc Double[] r = new Double[n]; r new Double[n] n for(int i=0;i<n;++i) r[i] = sc.nextDouble(); int i=0; int i=0; i 0 i<n i n ++i ++i i r[i] = sc.nextDouble(); r[i] = sc.nextDouble() r[i] r i sc.nextDouble() sc.nextDouble sc Arrays.sort(r) Arrays.sort Arrays r double ans = r[0]; ans r[0] r 0 for(int i=1;i<n;++i) {
		ans = (ans+r[i])/2; 
	} int i=1; int i=1; i 1 i<n i n ++i ++i i {
		ans = (ans+r[i])/2; 
	} {
		ans = (ans+r[i])/2; 
	} ans = (ans+r[i])/2 ans (ans+r[i])/2 (ans+r[i]) ans r[i] r i 2 out.print(ans) out.print out ans out.close() out.close out String[] args args public static class FastReader {
		BufferedReader br;
		StringTokenizer st;
	

		public FastReader() {
			br = new BufferedReader(new InputStreamReader(System.in));
		}

		String next() {
			while (st == null || !st.hasMoreTokens()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (Exception r) {
					r.printStackTrace();
				}
			}
			return st.nextToken();
		}

		int nextInt() {
			return Integer.parseInt(next());//converts string to integer
		}

		double nextDouble() {
			return Double.parseDouble(next());
		}

		long nextLong() {
			return Long.parseLong(next());
		}

		String nextLine() {
			String str = "";
			try {
				str = br.readLine();
			} catch (Exception r) {
				r.printStackTrace();
			}
			return str;
		}
	} FastReader BufferedReader br; br StringTokenizer st; st public FastReader() {
			br = new BufferedReader(new InputStreamReader(System.in));
		} FastReader {
			br = new BufferedReader(new InputStreamReader(System.in));
		} br = new BufferedReader(new InputStreamReader(System.in)) br new BufferedReader(new InputStreamReader(System.in)) String next() {
			while (st == null || !st.hasMoreTokens()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (Exception r) {
					r.printStackTrace();
				}
			}
			return st.nextToken();
		} next {
			while (st == null || !st.hasMoreTokens()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (Exception r) {
					r.printStackTrace();
				}
			}
			return st.nextToken();
		} while (st == null || !st.hasMoreTokens()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (Exception r) {
					r.printStackTrace();
				}
			} st == null || !st.hasMoreTokens() st == null st null !st.hasMoreTokens() st.hasMoreTokens() st.hasMoreTokens st {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (Exception r) {
					r.printStackTrace();
				}
			} try {
					st = new StringTokenizer(br.readLine());
				} catch (Exception r) {
					r.printStackTrace();
				} catch (Exception r) {
					r.printStackTrace();
				} Exception r {
					r.printStackTrace();
				} r.printStackTrace() r.printStackTrace r {
					st = new StringTokenizer(br.readLine());
				} st = new StringTokenizer(br.readLine()) st new StringTokenizer(br.readLine()) return st.nextToken(); st.nextToken() st.nextToken st int nextInt() {
			return Integer.parseInt(next());//converts string to integer
		} nextInt {
			return Integer.parseInt(next());//converts string to integer
		} return Integer.parseInt(next());//converts string to integer Integer.parseInt(next()) Integer.parseInt Integer next() next double nextDouble() {
			return Double.parseDouble(next());
		} nextDouble {
			return Double.parseDouble(next());
		} return Double.parseDouble(next()); Double.parseDouble(next()) Double.parseDouble Double next() next long nextLong() {
			return Long.parseLong(next());
		} nextLong {
			return Long.parseLong(next());
		} return Long.parseLong(next()); Long.parseLong(next()) Long.parseLong Long next() next String nextLine() {
			String str = "";
			try {
				str = br.readLine();
			} catch (Exception r) {
				r.printStackTrace();
			}
			return str;
		} nextLine {
			String str = "";
			try {
				str = br.readLine();
			} catch (Exception r) {
				r.printStackTrace();
			}
			return str;
		} String str = ""; str "" try {
				str = br.readLine();
			} catch (Exception r) {
				r.printStackTrace();
			} catch (Exception r) {
				r.printStackTrace();
			} Exception r {
				r.printStackTrace();
			} r.printStackTrace() r.printStackTrace r {
				str = br.readLine();
			} str = br.readLine() str br.readLine() br.readLine br return str; str public class Main {
	
	public static class FastReader {
		BufferedReader br;
		StringTokenizer st;
	

		public FastReader() {
			br = new BufferedReader(new InputStreamReader(System.in));
		}

		String next() {
			while (st == null || !st.hasMoreTokens()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (Exception r) {
					r.printStackTrace();
				}
			}
			return st.nextToken();
		}

		int nextInt() {
			return Integer.parseInt(next());//converts string to integer
		}

		double nextDouble() {
			return Double.parseDouble(next());
		}

		long nextLong() {
			return Long.parseLong(next());
		}

		String nextLine() {
			String str = "";
			try {
				str = br.readLine();
			} catch (Exception r) {
				r.printStackTrace();
			}
			return str;
		}
	}
	
	public static PrintWriter out = new PrintWriter (new BufferedOutputStream(System.out));
    public static long mod = (long) (1e9+7);
    public final static int MAX = (int)1e5;
  // static Scanner sc = new Scanner(System.in);
   static List<Integer>[] edge;
	public static void main(String[] args) {
	   
	 FastReader sc = new FastReader();
	int n = sc.nextInt();
	Double[] r = new Double[n];
	for(int i=0;i<n;++i) r[i] = sc.nextDouble();
	Arrays.sort(r);
	double ans = r[0];
	for(int i=1;i<n;++i) {
		ans = (ans+r[i])/2; 
	}
	out.print(ans);
		out.close();
	}
	
	
} public class Main {
	
	public static class FastReader {
		BufferedReader br;
		StringTokenizer st;
	

		public FastReader() {
			br = new BufferedReader(new InputStreamReader(System.in));
		}

		String next() {
			while (st == null || !st.hasMoreTokens()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (Exception r) {
					r.printStackTrace();
				}
			}
			return st.nextToken();
		}

		int nextInt() {
			return Integer.parseInt(next());//converts string to integer
		}

		double nextDouble() {
			return Double.parseDouble(next());
		}

		long nextLong() {
			return Long.parseLong(next());
		}

		String nextLine() {
			String str = "";
			try {
				str = br.readLine();
			} catch (Exception r) {
				r.printStackTrace();
			}
			return str;
		}
	}
	
	public static PrintWriter out = new PrintWriter (new BufferedOutputStream(System.out));
    public static long mod = (long) (1e9+7);
    public final static int MAX = (int)1e5;
  // static Scanner sc = new Scanner(System.in);
   static List<Integer>[] edge;
	public static void main(String[] args) {
	   
	 FastReader sc = new FastReader();
	int n = sc.nextInt();
	Double[] r = new Double[n];
	for(int i=0;i<n;++i) r[i] = sc.nextDouble();
	Arrays.sort(r);
	double ans = r[0];
	for(int i=1;i<n;++i) {
		ans = (ans+r[i])/2; 
	}
	out.print(ans);
		out.close();
	}
	
	
} Main


import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.math.BigInteger;
import java.util.*;


public class Main {
	
	public static class FastReader {
		BufferedReader br;
		StringTokenizer st;
	

		public FastReader() {
			br = new BufferedReader(new InputStreamReader(System.in));
		}

		String next() {
			while (st == null || !st.hasMoreTokens()) {
				try {
					st = new StringTokenizer(br.readLine());
				} catch (Exception r) {
					r.printStackTrace();
				}
			}
			return st.nextToken();
		}

		int nextInt() {
			return Integer.parseInt(next());//converts string to integer
		}

		double nextDouble() {
			return Double.parseDouble(next());
		}

		long nextLong() {
			return Long.parseLong(next());
		}

		String nextLine() {
			String str = "";
			try {
				str = br.readLine();
			} catch (Exception r) {
				r.printStackTrace();
			}
			return str;
		}
	}
	
	public static PrintWriter out = new PrintWriter (new BufferedOutputStream(System.out));
    public static long mod = (long) (1e9+7);
    public final static int MAX = (int)1e5;
  // static Scanner sc = new Scanner(System.in);
   static List<Integer>[] edge;
	public static void main(String[] args) {
	   
	 FastReader sc = new FastReader();
	int n = sc.nextInt();
	Double[] r = new Double[n];
	for(int i=0;i<n;++i) r[i] = sc.nextDouble();
	Arrays.sort(r);
	double ans = r[0];
	for(int i=1;i<n;++i) {
		ans = (ans+r[i])/2; 
	}
	out.print(ans);
		out.close();
	}
	
	
}
