#include <bits/stdc++.h>
using namespace std;
inline bool is_beau(string &s) {
  bool ret = true;
  int c = 0;
  for (int i = int(0); i < int(int(s.size())); ++i) {
    if (s[i] != '0' && s[i] != '1') ret = false;
    if (s[i] == '1') c++;
  }
  if (c > 1) ret = false;
  return ret;
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  int n;
  cin >> n;
  string ans, s;
  int zeros = 0;
  for (int i = int(0); i < int(n); ++i) {
    cin >> s;
    if (is_beau(s)) {
      if (s == "0") {
        cout << s << endl;
        return 0;
      } else
        zeros += int(s.size()) - 1;
    } else
      ans = s;
  }
  if (ans == "") ans.push_back('1');
  for (int i = int(0); i < int(zeros); ++i) ans.push_back('0');
  cout << ans << endl;
  return 0;
}
