#include<iosteram>
using namespace std;

int main(){
    int n;
    cin>>n;
    
    if(n<0){
        cout<<"Invalid input";
        return 0;
    }
    
    int deposit,total = 0;
    
    for(int i=0;i<n;i++){
        cin>>deposit;
        if(deposit<0){
            cout<<"Invalid input";
            return 0;
        }
        total +=deposit;
    }
    
    cout<<total;
    return 0;
}