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