#include<stdio.h>

int main(){
    int n;
    scanf("%d",&n);
    int score[n];
    float sum=0;avg;
    for(int i=0;i<n;i++){
        scanf("%d",&score[i]);
        if(score[i]<0 || score[i]>100){
            printf("Invalid input");
            return 0;
        }
    }
    for(int i=0;i<n;i++){
        sum += score[i];
    }
    avg = sum/n;
    printf("%.2f",avg);
    return 0;
}