#include<iostream>
using namespace std;
int main()
{
    int n;
    cin>> n;
    try{
        if (n <=0 || n > 12){
            throw"Invalid input";
        }
        double deposit,total = 0;
        for (int i =0;i < n;i++){
            cin>>deposit;
            if (deposit< 0){
                throw"Invalid input";
                
            }
            total +=deposit;
            
        }
        cout<<tot;
    }
    catch(const char*a)
    {
        cout<<a;
    }
}