#include<iostream>
using namespace std;
int main(){
    int n;
    cin>>n;
    try{
        if(n<=|| n>12){
            throw"Invalid input";
        }
        int dep,total=0;
        for(int i=0;i<n;i++){
            cin>>dep;
            if(dep<0){
                throw"invalid input";
            }
            total+=dep;
        }
        cout<<total;
    }
    catch(const chat* msg){
        cout<<msg;
}
return 0;
}