import java.util.*;
import java.math.*;

public class Main {
  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);
    
    String newV[] = new String[N-1];
    double sum01 = ((double)v[0]/2 + (double)v[1]/2);
    newV[0] = String.valueOf(sum01);
    if(N>1) {
      for(int j=1; j<N-1; j++) {
        String val1 = newV[j-1];
        String val2 = String.valueOf(v[j+1]);
        BigDecimal bd1 = new BigDecimal(val1);
        BigDecimal bd2 = new BigDecimal(val2);
        BigDecimal sum =bd1.add(bd2);
        BigDecimal two = new BigDecimal(2.0);
        BigDecimal result = sum.divide(two);
        newV[j] = result.toString();
    	}
    }
    
    System.out.println(newV[N-2]);
  }
} import java.util.*; util.* java import java.math.*; math.* java public class Main {
  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);
    
    String newV[] = new String[N-1];
    double sum01 = ((double)v[0]/2 + (double)v[1]/2);
    newV[0] = String.valueOf(sum01);
    if(N>1) {
      for(int j=1; j<N-1; j++) {
        String val1 = newV[j-1];
        String val2 = String.valueOf(v[j+1]);
        BigDecimal bd1 = new BigDecimal(val1);
        BigDecimal bd2 = new BigDecimal(val2);
        BigDecimal sum =bd1.add(bd2);
        BigDecimal two = new BigDecimal(2.0);
        BigDecimal result = sum.divide(two);
        newV[j] = result.toString();
    	}
    }
    
    System.out.println(newV[N-2]);
  }
} Main 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);
    
    String newV[] = new String[N-1];
    double sum01 = ((double)v[0]/2 + (double)v[1]/2);
    newV[0] = String.valueOf(sum01);
    if(N>1) {
      for(int j=1; j<N-1; j++) {
        String val1 = newV[j-1];
        String val2 = String.valueOf(v[j+1]);
        BigDecimal bd1 = new BigDecimal(val1);
        BigDecimal bd2 = new BigDecimal(val2);
        BigDecimal sum =bd1.add(bd2);
        BigDecimal two = new BigDecimal(2.0);
        BigDecimal result = sum.divide(two);
        newV[j] = result.toString();
    	}
    }
    
    System.out.println(newV[N-2]);
  } 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);
    
    String newV[] = new String[N-1];
    double sum01 = ((double)v[0]/2 + (double)v[1]/2);
    newV[0] = String.valueOf(sum01);
    if(N>1) {
      for(int j=1; j<N-1; j++) {
        String val1 = newV[j-1];
        String val2 = String.valueOf(v[j+1]);
        BigDecimal bd1 = new BigDecimal(val1);
        BigDecimal bd2 = new BigDecimal(val2);
        BigDecimal sum =bd1.add(bd2);
        BigDecimal two = new BigDecimal(2.0);
        BigDecimal result = sum.divide(two);
        newV[j] = result.toString();
    	}
    }
    
    System.out.println(newV[N-2]);
  } 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 String newV[] = new String[N-1]; newV new String[N-1] N-1 N 1 double sum01 = ((double)v[0]/2 + (double)v[1]/2); sum01 ((double)v[0]/2 + (double)v[1]/2) (double)v[0]/2 (double)v[0] v 0 2 (double)v[1]/2 (double)v[1] v 1 2 newV[0] = String.valueOf(sum01) newV[0] newV 0 String.valueOf(sum01) String.valueOf String sum01 if(N>1) {
      for(int j=1; j<N-1; j++) {
        String val1 = newV[j-1];
        String val2 = String.valueOf(v[j+1]);
        BigDecimal bd1 = new BigDecimal(val1);
        BigDecimal bd2 = new BigDecimal(val2);
        BigDecimal sum =bd1.add(bd2);
        BigDecimal two = new BigDecimal(2.0);
        BigDecimal result = sum.divide(two);
        newV[j] = result.toString();
    	}
    } N>1 N 1 {
      for(int j=1; j<N-1; j++) {
        String val1 = newV[j-1];
        String val2 = String.valueOf(v[j+1]);
        BigDecimal bd1 = new BigDecimal(val1);
        BigDecimal bd2 = new BigDecimal(val2);
        BigDecimal sum =bd1.add(bd2);
        BigDecimal two = new BigDecimal(2.0);
        BigDecimal result = sum.divide(two);
        newV[j] = result.toString();
    	}
    } for(int j=1; j<N-1; j++) {
        String val1 = newV[j-1];
        String val2 = String.valueOf(v[j+1]);
        BigDecimal bd1 = new BigDecimal(val1);
        BigDecimal bd2 = new BigDecimal(val2);
        BigDecimal sum =bd1.add(bd2);
        BigDecimal two = new BigDecimal(2.0);
        BigDecimal result = sum.divide(two);
        newV[j] = result.toString();
    	} int j=1; int j=1; j 1 j<N-1 j N-1 N 1 j++ j++ j {
        String val1 = newV[j-1];
        String val2 = String.valueOf(v[j+1]);
        BigDecimal bd1 = new BigDecimal(val1);
        BigDecimal bd2 = new BigDecimal(val2);
        BigDecimal sum =bd1.add(bd2);
        BigDecimal two = new BigDecimal(2.0);
        BigDecimal result = sum.divide(two);
        newV[j] = result.toString();
    	} {
        String val1 = newV[j-1];
        String val2 = String.valueOf(v[j+1]);
        BigDecimal bd1 = new BigDecimal(val1);
        BigDecimal bd2 = new BigDecimal(val2);
        BigDecimal sum =bd1.add(bd2);
        BigDecimal two = new BigDecimal(2.0);
        BigDecimal result = sum.divide(two);
        newV[j] = result.toString();
    	} String val1 = newV[j-1]; val1 newV[j-1] newV j-1 j 1 String val2 = String.valueOf(v[j+1]); val2 String.valueOf(v[j+1]) String.valueOf String v[j+1] v j+1 j 1 BigDecimal bd1 = new BigDecimal(val1); bd1 new BigDecimal(val1) BigDecimal bd2 = new BigDecimal(val2); bd2 new BigDecimal(val2) BigDecimal sum =bd1.add(bd2); sum bd1.add(bd2) bd1.add bd1 bd2 BigDecimal two = new BigDecimal(2.0); two new BigDecimal(2.0) BigDecimal result = sum.divide(two); result sum.divide(two) sum.divide sum two newV[j] = result.toString() newV[j] newV j result.toString() result.toString result System.out.println(newV[N-2]) System.out.println System.out System System.out newV[N-2] newV N-2 N 2 String[] args args public class Main {
  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);
    
    String newV[] = new String[N-1];
    double sum01 = ((double)v[0]/2 + (double)v[1]/2);
    newV[0] = String.valueOf(sum01);
    if(N>1) {
      for(int j=1; j<N-1; j++) {
        String val1 = newV[j-1];
        String val2 = String.valueOf(v[j+1]);
        BigDecimal bd1 = new BigDecimal(val1);
        BigDecimal bd2 = new BigDecimal(val2);
        BigDecimal sum =bd1.add(bd2);
        BigDecimal two = new BigDecimal(2.0);
        BigDecimal result = sum.divide(two);
        newV[j] = result.toString();
    	}
    }
    
    System.out.println(newV[N-2]);
  }
} public class Main {
  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);
    
    String newV[] = new String[N-1];
    double sum01 = ((double)v[0]/2 + (double)v[1]/2);
    newV[0] = String.valueOf(sum01);
    if(N>1) {
      for(int j=1; j<N-1; j++) {
        String val1 = newV[j-1];
        String val2 = String.valueOf(v[j+1]);
        BigDecimal bd1 = new BigDecimal(val1);
        BigDecimal bd2 = new BigDecimal(val2);
        BigDecimal sum =bd1.add(bd2);
        BigDecimal two = new BigDecimal(2.0);
        BigDecimal result = sum.divide(two);
        newV[j] = result.toString();
    	}
    }
    
    System.out.println(newV[N-2]);
  }
} Main
import java.util.*;
import java.math.*;

public class Main {
  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);
    
    String newV[] = new String[N-1];
    double sum01 = ((double)v[0]/2 + (double)v[1]/2);
    newV[0] = String.valueOf(sum01);
    if(N>1) {
      for(int j=1; j<N-1; j++) {
        String val1 = newV[j-1];
        String val2 = String.valueOf(v[j+1]);
        BigDecimal bd1 = new BigDecimal(val1);
        BigDecimal bd2 = new BigDecimal(val2);
        BigDecimal sum =bd1.add(bd2);
        BigDecimal two = new BigDecimal(2.0);
        BigDecimal result = sum.divide(two);
        newV[j] = result.toString();
    	}
    }
    
    System.out.println(newV[N-2]);
  }
}