#include<iostream>
using namespace std;
class machine
{
    public:
    void addproduction(int items)
    {
        if(items<0)
        {
            std::cout<<"Invalid production"<<std::endl;
        }
        else
        {
            totalproduction += items;
        }
    }
};
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;
}