#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, zero = 0;
  bool ans = true;
  string s, tm = "";
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> s;
    if (s == "0") ans = false;
    bool ok = true;
    for (int j = 1; j < s.size(); j++) {
      if (s[j] != '0') ok = false;
    }
    if (s[0] != '1' || !ok)
      tm = s;
    else
      zero += s.size() - 1;
  }
  if (!ans) {
    cout << "0";
    return 0;
  }
  if (tm == "") {
    cout << "1";
    while (zero--) cout << "0";
  } else {
    cout << tm;
    while (zero--) cout << "0";
  }
}
