#include <bits/stdc++.h>
using namespace std;
int n;
string s;
int cnt;
string k = "1";
int main() {
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> s;
    if (s == "0") {
      cout << 0;
      return 0;
    }
    if (s == "1") {
      continue;
    }
    bool c = s[0] == '1';
    if (c) {
      for (int j = 1; j < s.length(); j++) {
        if (s[j] != '0') {
          c = false;
          break;
        }
      }
    }
    if (c) {
      cnt += s.length() - 1;
    } else {
      k = s;
    }
  }
  cout << k;
  for (int i = 0; i < cnt; i++) {
    cout << 0;
  }
  return 0;
}
