import java.util.*;
 
public class Main {
	
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        double total = 0.0;
        int[] e = new int[N];
        for (int i = 0; i < N; i++) {
			e[i] = sc.nextInt();
		}
        Arrays.sort(e);
        double tmp = 0.0;
        for (int i = 0; i < N; i++) {
        	if (i == 0) {
        		tmp = e[i];
        	}
        	tmp = (e[i] + tmp)/2.0;
        }
        System.out.println(tmp);
    }
} import java.util.*; util.* java public class Main {
	
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        double total = 0.0;
        int[] e = new int[N];
        for (int i = 0; i < N; i++) {
			e[i] = sc.nextInt();
		}
        Arrays.sort(e);
        double tmp = 0.0;
        for (int i = 0; i < N; i++) {
        	if (i == 0) {
        		tmp = e[i];
        	}
        	tmp = (e[i] + tmp)/2.0;
        }
        System.out.println(tmp);
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        double total = 0.0;
        int[] e = new int[N];
        for (int i = 0; i < N; i++) {
			e[i] = sc.nextInt();
		}
        Arrays.sort(e);
        double tmp = 0.0;
        for (int i = 0; i < N; i++) {
        	if (i == 0) {
        		tmp = e[i];
        	}
        	tmp = (e[i] + tmp)/2.0;
        }
        System.out.println(tmp);
    } main {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        double total = 0.0;
        int[] e = new int[N];
        for (int i = 0; i < N; i++) {
			e[i] = sc.nextInt();
		}
        Arrays.sort(e);
        double tmp = 0.0;
        for (int i = 0; i < N; i++) {
        	if (i == 0) {
        		tmp = e[i];
        	}
        	tmp = (e[i] + tmp)/2.0;
        }
        System.out.println(tmp);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc double total = 0.0; total 0.0 int[] e = new int[N]; e new int[N] N for (int i = 0; i < N; i++) {
			e[i] = sc.nextInt();
		} int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
			e[i] = sc.nextInt();
		} {
			e[i] = sc.nextInt();
		} e[i] = sc.nextInt() e[i] e i sc.nextInt() sc.nextInt sc Arrays.sort(e) Arrays.sort Arrays e double tmp = 0.0; tmp 0.0 for (int i = 0; i < N; i++) {
        	if (i == 0) {
        		tmp = e[i];
        	}
        	tmp = (e[i] + tmp)/2.0;
        } int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
        	if (i == 0) {
        		tmp = e[i];
        	}
        	tmp = (e[i] + tmp)/2.0;
        } {
        	if (i == 0) {
        		tmp = e[i];
        	}
        	tmp = (e[i] + tmp)/2.0;
        } if (i == 0) {
        		tmp = e[i];
        	} i == 0 i 0 {
        		tmp = e[i];
        	} tmp = e[i] tmp e[i] e i tmp = (e[i] + tmp)/2.0 tmp (e[i] + tmp)/2.0 (e[i] + tmp) e[i] e i tmp 2.0 System.out.println(tmp) System.out.println System.out System System.out tmp String[] args args public class Main {
	
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        double total = 0.0;
        int[] e = new int[N];
        for (int i = 0; i < N; i++) {
			e[i] = sc.nextInt();
		}
        Arrays.sort(e);
        double tmp = 0.0;
        for (int i = 0; i < N; i++) {
        	if (i == 0) {
        		tmp = e[i];
        	}
        	tmp = (e[i] + tmp)/2.0;
        }
        System.out.println(tmp);
    }
} public class Main {
	
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        double total = 0.0;
        int[] e = new int[N];
        for (int i = 0; i < N; i++) {
			e[i] = sc.nextInt();
		}
        Arrays.sort(e);
        double tmp = 0.0;
        for (int i = 0; i < N; i++) {
        	if (i == 0) {
        		tmp = e[i];
        	}
        	tmp = (e[i] + tmp)/2.0;
        }
        System.out.println(tmp);
    }
} Main
import java.util.*;
 
public class Main {
	
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        double total = 0.0;
        int[] e = new int[N];
        for (int i = 0; i < N; i++) {
			e[i] = sc.nextInt();
		}
        Arrays.sort(e);
        double tmp = 0.0;
        for (int i = 0; i < N; i++) {
        	if (i == 0) {
        		tmp = e[i];
        	}
        	tmp = (e[i] + tmp)/2.0;
        }
        System.out.println(tmp);
    }
}