#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;
}