#include<stdio.h>
int main()
{
    int count;
    if(scanf("%d", &count) ! = 1);
    {
        printf(" No readings provider.\n");
        return 0;
    }
    if (count <=0)
    {
        printf("No readings provider.\n");
        return 0;
    }
    double sum = 0.0;
    int temp_reading;
    for (int i =0;i<count;i++)
    {
       if (scanf("%d",&temp_reading) !=1) 
       {
            break;
       }
       sum+=temp_reading;
    }
    double average =sum/count;
    printf("%.2f\n",average);
    return 0;

}