#include<iostream>
using namespace std;
int main(){
    int n;
    cin>>n;
    
    try{
        if(n<1 || n> 10){
            throw"Invalid input";
        }
        double grade,sum=0;
        for(int i=0;i<n;i++)
        {
            cin>>grade;
            if(grade<0){
                throw"Invalid input";
            }
            sum+=grade;
        }
        double gpa=sum/n;
        cout<<a;
    }
    return 0;
}