#include<iostream>
#include<iomanip>
using namespace std;
class Rainfall
{
    public:
    
    static double totalRainfall;
    static bool calculate(double value)
    {
        if (value<0)
        {
            cout<<"Invalid Rainfall";
            return false;
        }
        totalRainfall += value;
        return true;
    }
};

double Rainfall::totalRainfall =0;
int main()
{
    int n;
    cin>>n;
    if(cin.fail())
    {
        cout<<"Incomplet Data";
        return 0;
    }
    double rain;
    int count=0;
    for (int i=0;i<n;i++)
    {
        if(!(cin>>rain))
        {
            cout<<"Incomplet Data";
            return 0;
        }
        if(!Rainfall::calculate(rain))
        {
            return 0;
        }
        cout++;
    }
    cout<<fixed<<setprecision(2)<<Rainfall::totalRainfall;
    return 0;
}