#include<iostream>
using namespace std;
int main(){
    int n;
    cin>>n;
    try{
        if(n<0 ||n>12) {throw "invalid input";}
        double deposit[n];
        double sum = 0;
        for (int i = 0;i<n;i++){
            cin>>deposit[n];
            if (deposit <0 ){ throw "Invalid input";}
            sum +=deposit[n];
        }
        cout<<sum;
    }
    catch (const char*msg) {cout<<msg;}
    return 0;
}