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