#include <iostream>
using namespace std;

int main()
{
    
    int n;
    cin >> n;
    bool f = false;
    
    int sum = 0;
    int x;
    
    if((n>=1 && n<=10))
    {
    for(int i=0;i<n;i++)
    {
         cin >> x[i];
         sum += x[i];
         
         if(!(v[i]>=0 && v[i]<=10))
         {
             f = true;
             
         }

    }
    if(f)
    {
     cout<< "Invalid input";
     
    }
    else
    {
        cout<< (float) sum/n;
    }
}
else
{
    cout<<"Input invalid";
}
    return 0;
    }