#include<stdio.h>
#include<stdlib.h>
void calculate_average(){
    int count,temp,sum = 0;
    float average;
    if (scanf("%d" , &count) != 1){
        return 0;
    }
    if (count == 0){
        printf("No readings provided\n");
        return;
    }
    for(int i = 0; i < count; i++){
        if(scanf("%d", &temp) == 1){
            sum += temp;
        } else {
            break;l
        }
    }
    average = (float)sum / count;
    printf("%.2f\n", average);
}
int main(){
    calculate_average();
    return 0;
}