#include<stdio.h>
int main(){
    int n,ind;
    scanf("%d",&n);
    int arr[n];
    float sum,avg;
    for(ind=0;ind<n;ind++){
        if(scanf("%d",&arr[ind])!=1)){
            printf("Invalid input");
            return 0;
        }
        sum+=arr[ind];
    }
    avg=sum/n;
    printf("%.2f",avg);
    return 0;
}