#include <iostream>
using namespace std;

int main() {
    int n;
    cin >> n;
    try{
        if ( n < 0 || n > 12) {
            throw "Invalid input";
       }
       double deposit;
       double 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;
    }
}