#include<stdio.h>
float findavege(int arr[],int n)
{
    if(n==0)
    {
        return 0;
    }
    int sum=0;
    for(int i=0;i<n;i++)
    {
        sum+=arr[i];
   }
   return (float)sum/n;
}
int main()
{
    int n;
    scanf("%d",&n);
    if(n==0
    {
        prinf("no reading provided");
        return 0; 
        
    }
        inr arr[n];
        for (int i=0;i<n;i++)
        {
            scanf("%d",&arr[i]);
        }
        float avg =findaverage(arr,n);
        if(avg==-9999)
        {
            printf("no readings provided");
        }
        else
        {
            printf("%.2f",avg);
        }
        return 0;
}
        
        }
        }
    })
}
}