#include <bits/stdc++.h>
using namespace std;
const int dy[] = {-1, 0, 1, 0}, dx[] = {0, 1, 0, -1};
const double EPS = 1e-8;
const double PI = acos(-1.0);
int popcount(int n) { return __builtin_popcount(n); }
int popcount(long long n) { return __builtin_popcountll(n); }
template <class T>
int SIZE(T a) {
  return a.size();
}
template <class T>
string IntToString(T num) {
  string res;
  stringstream ss;
  ss << num;
  return ss.str();
}
template <class T>
T StringToInt(string str) {
  T res = 0;
  for (int i = 0; i < SIZE(str); i++) res = (res * 10 + str[i] - '0');
  return res;
}
template <class T>
T gcd(T a, T b) {
  if (b == 0) return a;
  return gcd(b, a % b);
}
template <class T>
T lcm(T a, T b) {
  return a / gcd(a, b) * b;
}
template <class T>
void PrintSeq(T &a, int sz) {
  for (int i = 0; i < sz; i++) {
    cout << a[i];
    if (sz == i + 1)
      cout << endl;
    else
      cout << ' ';
  }
}
long long getTen(int a) { return (a <= 0) ? 1 : (getTen(a - 1) * 10); }
bool EQ(double a, double b) { return abs(a - b) < EPS; }
void fastStream() {
  cin.tie(0);
  std::ios_base::sync_with_stdio(0);
}
vector<string> split(string str, char del) {
  vector<string> res;
  for (int i = 0, s = 0; i < SIZE(str); i++) {
    if (str[i] == del) {
      if (i - s != 0) res.push_back(str.substr(s, i - s));
      s = i + 1;
    } else if (i == SIZE(str) - 1) {
      res.push_back(str.substr(s));
    }
  }
  return res;
}
int N;
int as[1000];
int cnts[1000];
int res[1000];
int selected[1000];
int main() {
  memset(res, -1, sizeof(res));
  int l = 0, r = 0;
  cin >> N;
  for (int i = 0; i < 2 * N; i++) {
    cin >> as[i];
    cnts[as[i]]++;
  }
  for (int i = 0; i < 2 * N; i++) {
    if (cnts[as[i]] > 1) {
      if (selected[as[i]] == 0) {
        res[i] = false;
        selected[as[i]]++;
        l++;
      } else if (selected[as[i]] == 1) {
        res[i] = true;
        selected[as[i]]++;
        r++;
      }
    }
  }
  for (int i = 0; i < 2 * N; i++) {
    if (cnts[as[i]] == 1) {
      if (l <= r) {
        l++;
        res[i] = false;
      } else {
        r++;
        res[i] = true;
      }
    }
  }
  for (int i = 0; i < 2 * N; i++) {
    if (res[i] == -1) {
      if (l < N)
        res[i] = false, l++;
      else
        res[i] = true;
    }
  }
  set<int> st1, st2;
  for (int i = 0; i < 2 * N; i++)
    if (res[i])
      st1.insert(as[i]);
    else
      st2.insert(as[i]);
  cout << st1.size() * st2.size() << endl;
  for (int i = 0; i < 2 * N; i++) {
    cout << res[i] + 1;
    if (i == 2 * N - 1)
      cout << endl;
    else
      cout << " ";
  }
  return 0;
}
