#include<iostream>
#include<iomanip>
#include<vector>
using namespace std;
class RainfallTracker{
    private:
    static double totalRainfall;
    public:
    static void addRainfall(double amount){
        totalRainfall += amount;
    }
    static double getTotal(){
        return totalRainfall;
    }
};
double RainfallTracker::totalRainfall = 0.0;
int main()
{
    int n;
    if(!(cin>>n)){
        return 0;
    }
    double currentRainfall;
    for(int i=0; i<n; ++i){
        if(!(cin>>currentRainfall)){
        cout<<"Incomplete Data"<< endl;
        return 0;
    }
    if(currentRainfall < 0){
        cout<<"Invalid Rainfall"<<endl;
        return 0;
    }
    RainfallTracker::addRainfall(currentRainfall);
    }
    cout<< fixed << setprecision(2) << RainfallTracker::gettotal()<<endl;
    return 0;
}