#include <bits/stdc++.h>
using namespace std;
int ok, num;
bool check(string &t) {
  int x1 = 0, tnum = 0;
  for (int i = 0; i < t.size(); i++) {
    if (t[i] != '1' && t[i] != '0') {
      return false;
    }
    if (t[i] == '1')
      x1++;
    else {
      ++tnum;
    }
  }
  if (x1 == 0) ok = 0;
  if (x1 <= 1) num += tnum;
  return x1 <= 1;
}
int main() {
  int n, i;
  cin >> n;
  string p;
  ok = 1;
  for (i = 0; i < n; i++) {
    string a;
    cin >> a;
    if (!check(a)) p = a;
  }
  if (ok) {
    if (p == "") p = "1";
    cout << p;
    for (i = 0; i < num; i++) cout << 0;
    cout << endl;
  } else
    cout << 0 << endl;
  return 0;
}
