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