#include <bits/stdc++.h>
using namespace std;
void solve(void);
int main() {
  {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    { solve(); }
  }
  return 0;
}
void solve() {
  long long int n, i, j, k;
  cin >> n;
  long long int a[n];
  set<string> se;
  string s, nb = "1";
  vector<long long int> v;
  for (i = 0; i < n; i++) {
    cin >> s;
    se.insert(s);
    long long int c1 = 0, c = 0;
    for (j = 0; j < s.size(); j++) {
      if (s[j] == '0') {
        v.push_back(0);
        c1++;
      } else if (s[j] == '1') {
        c++;
      } else {
        c += 2;
      }
    }
    if (c > 1) {
      nb = s;
      for (k = 1; k <= c1; k++) v.pop_back();
    }
  }
  if (se.count("0")) {
    cout << "0" << endl;
    return;
  }
  cout << nb;
  for (auto x : v) cout << x;
  cout << endl;
}
