#include <iostream>
#include <vector>

using namespace std;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);

    int a;
    cin >> a;
    int cur = 0;
    string s = "";
    for (size_t i = 0; i < a; i++)
    {
        cur/=10;
        int b;
        cin >> b;
        cur+=b;
        //cout << cur << "\n";
    }
    for (size_t i = 0; i < a-1; i++)
    {
        s+='0';
    }
    cout << cur << s << "\n";
}