#include <bits/stdc++.h>
using namespace std;
int n, d, zero;
int main() {
  cin >> n;
  string s, ans = "1";
  while (n--) {
    cin >> s;
    d = 0;
    for (int i = 0; s[i]; i++) d += int(s[i]) - 48;
    if (!d) {
      cout << "0";
      return 0;
    } else if (d == 1)
      zero += s.size() - 1;
    else
      ans = s;
  }
  cout << ans;
  while (zero--) cout << "0";
  return 0;
}
