#include<stdio.h>
int main({
    int n;
    scanf("%d",&n);
    if(n <=0){
        printf("no readings provided");
        return 0;
    }
    double sum = 0;
    int temp;
    for(int i =0;i < n;i++){
        scanf("%d",&temp);
        sum += temp;
    }
    double average = sum/n;
    printf("%.2f",average);
    return 0;
}