#include <iostream>
using namespace std;
class Machine{
    public:
    static int totalProduction;
    void addProduction(int items){
        if (items<0){
            std::cut<<"Invalid Production"<<std::endl;
        }else{
            totalProduction += items;
        }
    }
};
int Machine::totalProduction = 0;

int main(){
    int n;
    std::cin>>n;
    for(int i=0; i<n; ++i){
        int itemsProduced;
        std::cin>>itemsProduced;
        Machine m;
        m.addProduction(itemsProduced);
    }
    std::cout<<Machine::totalProduction<<std::endl;
    return 0;
}