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