#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  string nonz;
  int ans = 0;
  string s = "";
  bool zr = false;
  for (int i = 0; i < n; i++) {
    string a;
    cin >> a;
    if (a == "0") zr = true;
    string x = a;
    bool beauty = true;
    int zero = 0, one = 0;
    for (auto j : a) {
      if (j == '1')
        one++;
      else if (j == '0')
        zero++;
      else {
        beauty = false;
        nonz = x;
      }
    }
    if (one > 1) {
      beauty = false;
      nonz = x;
    } else if (beauty) {
      ans += zero;
    }
  }
  if (!zr) {
    if (nonz.size())
      cout << nonz;
    else
      cout << 1;
    for (int i = 0; i < ans; i++) {
      cout << 0;
    }
    cout << endl;
  } else {
    cout << 0 << endl;
  }
}
