#include<iostream>
#include<iomanip>
using namespace std;
class Rainfall {
    public:
     static void calulate() {
         if (!(cin >> n)) {
             cout << "Incomplete Data";
             return 0;
         }
         double rain, total = 0;
         for (int i = 0; i < n; i ++;
         if (!(cin >> rain)) {
             cout << "Incomplete Data";
             return 0;
         }
         if (rain < 0){
             cout << "Invalid Rainfall";
             return;
         }
         total += rain;
     }
     cout << fixed << setprecision(2) << total;
}
};
int main(){
    Rainfall::calculate();
    return 0;
}