#include <bits/stdc++.h>
using namespace std;
bool isbt(string S) {
  if (S[0] != '1') return false;
  for (int i = 1; i < S.size(); i++)
    if (S[i] != '0') return false;
  return true;
}
int main() {
  int n;
  string u, rs = "1";
  int t = 0;
  cin >> n;
  bool f = true;
  while (n--) {
    cin >> u;
    if (isbt(u))
      t += (u.size() - 1);
    else if (u == "0")
      f = false;
    else
      rs = u;
  }
  if (!f) {
    cout << "0\n";
    return 0;
  }
  string res(t + rs.size(), '0');
  for (int i = 0; i < rs.size(); i++) res[i] = rs[i];
  cout << res << "\n";
  return 0;
}
