#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 <<total;
    }
    catch(const char*a)
    {
        const <<a;
    }
   }