#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  long long n, zero(0);
  string x, nonzero("Null");
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> x;
    long long one(0);
    if (x == "0") {
      cout << 0 << endl;
      return 0;
    }
    long long curr(0);
    bool f = 1;
    for (int j = 0; j < x.length(); j++) {
      if (x[j] == '1') {
        if (one == 0) {
          one++;
        } else if (one == 1) {
          nonzero = x;
          f = 0;
          break;
        }
      } else if (x[j] == '0') {
        curr++;
      } else {
        nonzero = x;
        f = 0;
        break;
      }
    }
    if (f) zero += curr;
  }
  if (nonzero == "Null") {
    cout << 1;
  } else {
    cout << nonzero;
  }
  for (int i = 0; i < zero; i++) {
    cout << 0;
  }
  cout << endl;
  return 0;
}
