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