#include <bits/stdc++.h>
using namespace std;
string k = "1";
int he(string s) {
  int p = 0, cnt = 0, u = 0;
  for (int i = 0; i < s.size(); i++) {
    if (s[i] == '1')
      p++;
    else if (s[i] == '0')
      cnt++;
    else
      u++;
  }
  if (p > 1) return 0;
  if (u) return 0;
  return 1;
}
int main() {
  int n, temp = 0, res = 0, d = 0;
  cin >> n;
  for (int i = 0; i < n; i++) {
    string s;
    cin >> s;
    if (s == "0") {
      res = 1;
    }
    if (!he(s)) {
      k = s;
    } else
      d += s.size() - 1;
  }
  if (res == 1) {
    cout << "0" << endl;
    return 0;
  }
  cout << k;
  for (int i = 0; i < d; i++) {
    cout << "0";
  }
  cout << endl;
}
