#include<stdio.h>
float findaverage(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)
    {
        printf("No readings provided");
        return 0;
    }
    int 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;
}