// editor15

import java.util.Scanner;
class Main{
    public static void main(String args[]){
        Scanner sc=new Scanner(System.in);
        String type=sc.next();
        if(!type.equalsIgnorecase("postgraduate")&&
        !type.equalsIgnorecase("undergraduate")){
        System.out.println("Invalid input");
        return;
    }
    String name=sc.next();
    if(!sc.hasNextInt()){
         System.out.println("Invalid input");
         return;
    }
    String id=sc.next();
    if(!sc.hasNextInt()){
         System.out.println("Invalid input");
         return;
    }
    int gradesno=sc.nextInt();
    if(gradesno<=0){
        System.out.println("Invalid input");
        return;
    }
    double sum=0;
    for(int i=0;i<gradesno;i++){
        if(!sc.hasNextInt()){
         System.out.println("Invalid input");
         return;
    }
        int grades=sc.nextInt();
        if(grades<0||grades>200){
            System.out.println("Invalid input");
         return;
        }
    sum+=grades;
    }
    double avg=sum/gradesno;
    System.out.printf("%.2f",avg);
}
}