#include <bits/stdc++.h>
bool isprime[100000];
using namespace std;
void setprime() {
  for (int i = 1; i < 100005; i++) isprime[i] = true;
  isprime[0] = false;
  isprime[1] = false;
  for (int i = 2; i * i < 100005; i++) {
    if (isprime[i] == true) {
      for (int j = (2 * i); j < 100005; j += i) isprime[j] = false;
    }
  }
}
long long mod = 1000000007;
long long N = 1000005;
long long abSolute(long long a) {
  if (a >= 0)
    return a;
  else
    return (-1) * a;
}
bool otherO(string t) {
  long long cl = 0, count = 0, l = t.length();
  if (l == 1 && t[0] == '1') return true;
  for (long long i = 0; i < l; i++) {
    if (t[i] != '0' && t[i] != '1') {
      return false;
    } else if (t[i] == '1')
      cl++;
  }
  if (cl == 1)
    return true;
  else
    return false;
}
long long countZero(string t) {
  long long count = 0, l = t.length();
  for (long long i = 0; i < l; i++) {
    if (t[i] == '0') count++;
  }
  return count;
}
int main() {
  cin.tie(0);
  ios::sync_with_stdio(0);
  cout << fixed;
  cout << setprecision(12);
  long long n, cn = 1, count = 0, zeroCnt = 0;
  cin >> n;
  string s, ans, bt;
  for (long long i = 0; i < n; i++) {
    bool flag = true;
    string temp;
    cin >> temp;
    if (temp == "0") {
      cout << 0;
      return 0;
    }
    if (cn != 0) {
      flag = otherO(temp);
      if (!flag) cn = 0;
    }
    if (!flag)
      bt = temp;
    else
      zeroCnt += countZero(temp);
  }
  if (cn == 0)
    ans += bt;
  else
    ans += '1';
  for (long long i = 0; i < zeroCnt; i++) ans += '0';
  cout << ans;
  return 0;
}
