#include<iostream>
#include<iomanip>
using namespace std;
class Rainfall{
    public:
    static double total;
    static void add(double r)
    {
        total +=
    };
};
double Rainfall::total=0;
int main(){
    int n;
    if(!(cin>>n))
    {
        cout<<"Incomplete Data";
        return 0;
    }
    for(int i=0;i<n;i++)
    {
        double val;
        if(!(cin>>val))
        {
            cout<<"Incomplete Data";
            return 0;
        }
        if(val<0)
        {
            cout<<"Invalid Rainfall";
            return 0;
        }
        Rainfall::add(val);
    }
    cout<<fixed<<setprecision(2)<<Rainfall::total<<endl;
    return 0;
}