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