#include <bits/stdc++.h>
using namespace std;
string s[100000];
int N;
int main() {
  cin >> N;
  int bad = -1;
  int zero = 0;
  bool null = 0;
  for (int i = 0; i < N; i++) {
    cin >> s[i];
    if (s[i].size() == 1 && s[i][0] == '0') null = 1;
    int cnt1 = 0;
    for (int j = 0; j < s[i].size(); j++) {
      if (s[i][j] == '0')
        continue;
      else if (s[i][j] == '1')
        cnt1++;
      else
        bad = i;
    }
    if (cnt1 > 1) bad = i;
    if (bad != i) {
      for (int j = 0; j < s[i].size(); j++)
        if (s[i][j] == '0') zero++;
    }
  }
  if (null) {
    cout << 0 << '\n';
    return 0;
  }
  if (bad == -1) {
    cout << 1;
    for (int i = 0; i < zero; i++) cout << 0;
    cout << '\n';
    return 0;
  }
  cout << s[bad];
  for (int i = 0; i < zero; i++) cout << '0';
  cout << '\n';
}
