#include<stdio.h>
#include<stdlib.h>
int main(){
    int n;
    if(scanf("%d",&n)  !=1) {
        printf("Invalid input");
        return;
    }
    scanf("%d",&n);
    if(n<0){
        printf("No readings provided");
        return 0;
    }
    int temp;
    float sum=0;
    for(int i =0;i<n;i++)
    {
        scanf("%d",&temp);
        sum += temp;
    }
    float avg=sum/n;
    printf("%0.2f",avg);
    return 0;
}