import java.util.*;
class a{
    public static void main(String[] args){
        Scanner scan =new Scanner(System.in);
        
        String str=scan.nextLine();
        String name=scan.nextLine();
        int id=scan.nextInt();
        int len=String.valueOf(id).length();
        if(len!=6){
            System.out.println("Invalid input");
            return;
        }
        int n=scan.nextInt();
        int[] arr=new int[n];
        double total=0;
        for(int j=0;j<n;j++){
            arr[j]=scan.nextInt();
        }
        for(int j=0;j<n;j++){
            arr[j]=scan.nextInt();
        }
        
        for(int j=0;j<n;j++){
            if(arr[i]<0){
                    System.out.println("Invalid input");
                    return;
            }
            
        }
        total/=n;
        
        System.out.printf("%.2f" ,total);

    }
}