#include <bits/stdc++.h>
using namespace std;
string s;
int check(string p) {
  int one = 0, zero = 0;
  for (int i = 0; i < p.size(); i++) {
    if (p[i] == '1') one++;
    if (p[i] != '0' && p[i] != '1') return -1;
  }
  return one;
}
int main() {
  int n;
  cin >> n;
  int len = 0, zr = 0;
  string fal;
  for (int i = 0; i < n; i++) {
    cin >> s;
    int one = check(s);
    if (one == -1 || one > 1)
      fal = s;
    else {
      if (one == 0) zr = 1;
      len += s.size() - 1;
    }
  }
  if (zr) {
    cout << 0 << endl;
    return 0;
  }
  if (fal.size())
    cout << fal;
  else
    cout << 1;
  for (int i = 0; i < len; i++) cout << 0;
}
