#include <bits/stdc++.h>
using namespace std;
long long gcd(long long a, long long b) { return (b == 0 ? a : gcd(b, a % b)); }
long long lcm(long long a, long long b) { return (a * (b / gcd(a, b))); }
int test(string s) {
  int zero = 0, ones = 0;
  ;
  for (int i = 0; i < int(s.length()); ++i) {
    if (s[i] != '0' && s[i] != '1')
      return -1;
    else if (s[i] == '1')
      ones++;
    else if (s[i] == '0')
      zero++;
  }
  if (ones > 1) return -1;
  return zero;
}
int main() {
  int n, res = 0;
  string print;
  cin >> n;
  for (int i = 0; i < int(n); ++i) {
    string s;
    cin >> s;
    if (s == "0") {
      cout << "0" << endl;
      return 0;
    }
    int x = test(s);
    if (x == -1)
      print = s;
    else
      res += x;
  }
  cout << print;
  if (print.size() == 0) cout << "1";
  for (int i = 0; i < int(res); ++i) cout << "0";
  cout << endl;
}
