#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;
}