#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* msg) {
            cout<<msg;
            
        }
        return 0;
}