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