#include <bits/stdc++.h>
using namespace std;
void fast_io() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
}
int isBeautiful(string x) {
  int o = 0, z = 0;
  for (char c : x) {
    if (c == '1')
      o++;
    else if (c == '0')
      z++;
  }
  if (o <= 1 && z + o == x.size()) {
    return z;
  }
  return -1;
}
void solve() {
  int n;
  cin >> n;
  int cnt_zeros = 0;
  string ans = "";
  for (int i = 0; i < n; i++) {
    string x;
    cin >> x;
    int z = isBeautiful(x);
    if (z != -1) {
      if (z == x.size()) {
        cout << "0\n";
        return;
      } else {
        cnt_zeros += z;
      }
    } else {
      ans = x;
    }
  }
  if (ans == "") {
    cout << "1";
  } else {
    cout << ans;
  }
  while (cnt_zeros--) {
    cout << "0";
  }
  cout << endl;
}
int main() {
  fast_io();
  solve();
  return 0;
}
