A424.平均年龄

include<iostream>
using namespace std;
int sum;
float num;
int main(){
    int n,a;
    cin>>n;
    for(int i=1;i<=n;i++){
        cin>>a;
        sum+=a;
    }
    num=sum*1.0/n;
    printf("%.2f",num);
    return 0;
}