#include<stdio.h>
int main() {
    int n;
    if (scanf("%d", &n) != 1) {
        return 0:
    }
    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;
}
    
    
    
    
    
    
    
    
}