#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, cnt = 0;
  cin >> n;
  string ans = "", unlucky, x;
  for (int i = 0; i < n; ++i) {
    int one = 0, zero = 0;
    cin >> x;
    if (x == "0") {
      cout << 0;
      return 0;
    } else if (x == "1")
      continue;
    for (int j = 0; j < x.size(); ++j) {
      if (x[j] == '1')
        one++;
      else if (x[j] == '0')
        zero++;
    }
    if (one == 1 && zero > 0)
      cnt += zero;
    else
      ans = x;
  }
  if (ans == "") ans = "1";
  for (int i = 0; i < cnt; ++i) ans += '0';
  if (ans[0] == '0') ans = ('1' + ans);
  cout << ans;
  return 0;
}
