#include <bits/stdc++.h>
using namespace std;
int isBeautiful(string s) {
  int ones = 0;
  int zero = 0;
  for (int i = 0; i < s.length(); i++) {
    if (s[i] == '1')
      ones++;
    else if (s[i] == '0')
      zero++;
    else
      return -1;
  }
  if (ones > 1) return -1;
  return zero;
}
int main() {
  ios::sync_with_stdio(false);
  int n;
  cin >> n;
  vector<int> a(n);
  string s;
  string ans = "";
  int zeros = 0;
  for (int i = 0; i < n; i++) {
    cin >> s;
    if (s.length() == 1 && s[0] == '0') ans = "0";
    int z = isBeautiful(s);
    if (z == -1 && ans != "0")
      ans.append(s);
    else
      zeros += z;
  }
  if (ans == "0") {
    cout << ans << endl;
    return 0;
  } else if (ans == "")
    ans = "1";
  ans.append(zeros, '0');
  cout << ans << endl;
  return 0;
}
