#include<iostream>
#include<iomanip>
using namespace std;

class Rainfall
{
    public:
    static double total;
    static bool addRainfall(double value)
    {
        if (value<0)
        {
            cout<<"Invalid Rainfall";
            return true;
        }
        total+= value;
        return false;
    }
};
double Rainfall::total=0;
int main()
{
    int n;
    if (!(cin>>n))
    {
        cout<<"Incomplete Data";
        return 0;
    }
    for(int i=0;i<n;i++)
    double rain;
    {
        if (!(cin>>rain))
        {
            cout<<"Incomplete Data";
            return 0;
        }
        if (!Rainfall::addRainfall(rain))
        {
            return 0;
        }
    }
    cout<<fixed<<setercision(2)<<Rainfall::total;
    return 0;
    
}