Problem:
Score : 400 points

Problem Statement

Snuke has decided to play a game using cards.
He has a deck consisting of N cards. On the i-th card from the top, an integer A_i is written.

He will perform the operation described below zero or more times, so that the values written on the remaining cards will be pairwise distinct. Find the maximum possible number of remaining cards. Here, N is odd, which guarantees that at least one card can be kept.

Operation: Take out three arbitrary cards from the deck. Among those three cards, eat two: one with the largest value, and another with the smallest value. Then, return the remaining one card to the deck.

Constraints

3 ≦ N ≦ 10^{5}

N is odd.

1 ≦ A_i ≦ 10^{5}

A_i is an integer.

Input

The input is given from Standard Input in the following format:

N
A_1 A_2 A_3 ... A_{N}

Output

Print the answer.

Sample Input 1

5
1 2 1 3 7

Sample Output 1

3

One optimal solution is to perform the operation once, taking out two cards with 1 and one card with 2. One card with 1 and another with 2 will be eaten, and the remaining card with 1 will be returned to deck. Then, the values written on the remaining cards in the deck will be pairwise distinct: 1, 3 and 7.

Sample Input 2

15
1 3 5 2 1 3 2 8 8 6 2 6 11 1 1

Sample Output 2

7

Solution in C# (Mono 4.6.2.0) (judge verdict: Accepted)

using System;
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Numerics;
using System.Runtime.InteropServices;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using static System.Math;
using static Math2;
using static Output;

public class CP {
  public void Solve () {
    Input sc = new Input ();
    int n = sc.cin<int> ();
    int[] a = sc.cinarr<int> ();
    if ((n - a.Distinct ().Count ()) % 2 == 0) Put (a.Distinct ().Count ());
    else Put (a.Distinct ().Count () - 1);
  }

}

public static class Math2 {
  public const int INF = 1 << 29;
  public const long INFL = 1L << 60;
  public const long MOD = 1000000007;
  public const long MOD2 = 998244353;

  public static long Power (long a, long b, long MOD = 1000000007) //i^N
  {
    long res = 1;
    while (b > 0) {
      if ((b & 1) != 0) res = res * a % MOD;
      a = a * a % MOD;
      b >>= 1;
    }
    return res;
  }
  public static long Power2 (long a, long b) //i^N
  {
    long res = 1;
    while (b > 0) {
      if ((b & 1) != 0) res = res * a;
      a = a * a;
      b >>= 1;
    }
    return res;
  }
  public static long GCD (long a, long b) {
    if (a == 0) return b;
    while (b > 0) {
      var r = a % b;
      a = b;
      b = r;
    }
    return a;
  }
  public static long LCM (long a, long b) => (b / GCD (a, b)) * a;
  public static long Comb (long n, long r, int MOD = 1000000007) {
    if (r > n - r) r = n - r;
    long Nume = 1;
    long Deno = 1;

    if (r > n - r) r = n - r;
    for (long i = 1; i <= r; ++i) {
      Deno = (Deno * i) % MOD;
      Nume = Nume * (n - i + 1) % MOD;
    }
    return (Nume * inv (Deno)) % MOD;
  }
  public static long Comb2 (long n, long r) {
    long Nume = 1;
    long Deno = 1;

    if (r > n - r) r = n - r;
    for (long i = 1; i <= r; ++i) {
      Deno *= i;
      Nume *= n - i + 1;
    }
    return Nume / Deno;
  }
  public static long inv (long x, int MOD = 1000000007) {
    return Power (x, MOD - 2, MOD);
  }
}
public static class Utils {
  public static void Swap<T> (ref T A, ref T B) {
    T x = A;
    A = B;
    B = x;
  }
  public static int DigitSum (string N) {

    int ret = 0;
    for (int i = 0; i < N.Length; ++i) ret += N[i] - '0';
    return ret;
  }
  public static string ConvertBase (long N, int K) {
    StringBuilder ret = new StringBuilder ();
    while (N > 0) {
      var r = N % K;
      N /= K;
      ret.Append (r);
    }
    return new string (ret.ToString ().ToCharArray ().Reverse ().ToArray ());
  }
  public static bool NextPermutation<T> (IList<T> lis, Comparison<T> cmp) {
    int n = lis.Count;
    int i = n - 1;
    while (i - 1 >= 0) {
      if (cmp (lis[i - 1], lis[i]) < 0) break;
      --i;
    }
    if (i == 0) return false;
    int j = i;
    while (j + 1 < n) {
      if (cmp (lis[i - 1], lis[j + 1]) > 0) break;
      ++j;
    }
    var _q = lis[j];
    lis[i - 1] = lis[j];
    lis[i - 1] = _q;
    int k = i;
    int l = n - 1;
    while (k < l) {
      var _p = lis[k];
      lis[l] = lis[k];
      lis[l] = _p;

      ++k;
      --l;
    }
    return true;
  }
  public static bool NextPermutation<T> (IList<T> lis) => NextPermutation (lis, Comparer<T>.Default.Compare);
}
public class PriorityQueue<T> {
  List<T> _item;
  public int Count { get { return _item.Count; } }
  bool _isascend { get; set; }
  public T Peek { get { return _item[0]; } }
  Comparison<T> Comp;
  public PriorityQueue (bool IsAscend = true, IEnumerable<T> list = null) : this (Comparer<T>.Default.Compare, IsAscend, list) { }
  public PriorityQueue (Comparison<T> cmp, bool IsAscend = true, IEnumerable<T> list = null) {
    _item = new List<T> ();
    _isascend = IsAscend;
    this.Comp = cmp;
    if (list != null) {
      _item.AddRange (list);
      Build ();
    }
  }

  private int Compare (int i, int j) => (_isascend ? -1 : 1) * Comp (_item[i], _item[j]);
  private void Swap (int i, int j) { var t = _item[i]; _item[i] = _item[j]; _item[j] = t; }
  private int Parent (int i) => (i - 1) >> 1;
  private int Left (int i) => (i << 1) + 1;
  public T Enqueue (T val) {
    int i = _item.Count;
    _item.Add (val);
    while (i > 0) {
      int p = Parent (i);
      if (Compare (i, p) > 0)
        Swap (i, p);
      i = p;
    }
    return val;
  }
  private void Heapify (int index) {
    for (int i = index, j;
      (j = Left (i)) < _item.Count; i = j) {
      if (j != _item.Count - 1 && Compare (j, j + 1) < 0) j++;
      if (Compare (i, j) < 0)
        Swap (i, j);
    }
  }
  public T Dequeue () {
    T val = _item[0];
    _item[0] = _item[_item.Count - 1];
    _item.RemoveAt (_item.Count - 1);
    Heapify (0);
    return val;
  }
  private void Build () {
    for (var i = (_item.Count >> 1) - 1; i >= 0; i--)
      Heapify (i);
  }
  public bool Any () => Count > 0;
}
class Program {
  static void Main (string[] args) {
    var CP = new CP ();
    CP.Solve ();
  }
}
public static class Output {

  public static void Put (string a) => Console.WriteLine (a);
  public static void Put (params object[] i) => Put (string.Join (" ", i));
  public static void Put<T> (IEnumerable<T> a) => Put (string.Join (" ", a));
  public static void PutV<T> (IEnumerable<T> a) { foreach (var z in a) Put (z); }
  public static void YN (bool i) {
    if (i) Put ("Yes");
    else Put ("No");
  }
}
public class Input {
  public static string Str => Console.ReadLine ();
  public static bool IsTypeEqual<T, U> () => typeof (T).Equals (typeof (U));
  public static T ConvertType<T, U> (U a) => (T) Convert.ChangeType (a, typeof (T));
  public static T Cast<T> (string s) {
    if (IsTypeEqual<T, int> ()) return ConvertType<T, int> (int.Parse (s));
    else if (IsTypeEqual<T, long> ()) return ConvertType<T, long> (long.Parse (s));
    else if (IsTypeEqual<T, double> ()) return ConvertType<T, double> (double.Parse (s));
    else if (IsTypeEqual<T, char> ()) return ConvertType<T, char> (char.Parse (s));
    else return ConvertType<T, string> (s);
  }
  public static T[] Castarr<T> (string[] s) {

    var ret = new T[s.Length];
    int i = 0;
    if (IsTypeEqual<T, char> ()) {
      var list = new List<T> ();
      foreach (var t in s) {
        foreach (var u in t) {
          list.Add (ConvertType<T, char> (char.Parse (u.ToString ())));
        }
      }
      return list.ToArray ();
    }
    foreach (var t in s) {
      if (IsTypeEqual<T, int> ()) ret[i++] = ConvertType<T, int> (int.Parse (t));
      else if (IsTypeEqual<T, long> ()) ret[i++] = ConvertType<T, long> (long.Parse (t));
      else if (IsTypeEqual<T, double> ()) ret[i++] = ConvertType<T, double> (double.Parse (t));
      else ret[i++] = ConvertType<T, string> (t);
    }
    return ret;
  }
  Queue<string> q = new Queue<string> ();
  void next () { var ss = Str.Split (' '); foreach (var item in ss) q.Enqueue (item); }
  public T cin<T> () { if (!q.Any ()) next (); return Cast<T> (q.Dequeue ()); }
  public void mul<T> (out T t) { t = cin<T> (); }
  public void mul<T, U> (out T t, out U u) { t = cin<T> (); u = cin<U> (); }
  public void mul<T, U, V> (out T t, out U u, out V v) { t = cin<T> (); u = cin<U> (); v = cin<V> (); }
  public void mul<T, U, V, W> (out T t, out U u, out V v, out W w) { t = cin<T> (); u = cin<U> (); v = cin<V> (); w = cin<W> (); }
  public void mul<T, U, V, W, X> (out T t, out U u, out V v, out W w, out X x) { t = cin<T> (); u = cin<U> (); v = cin<V> (); w = cin<W> (); x = cin<X> (); }
  public void mul<T, U, V, W, X, Y> (out T t, out U u, out V v, out W w, out X x, out Y y) { t = cin<T> (); u = cin<U> (); v = cin<V> (); w = cin<W> (); x = cin<X> (); y = cin<Y> (); }
  public void mul<T, U, V, W, X, Y, Z> (out T t, out U u, out V v, out W w, out X x, out Y y, out Z z) { t = cin<T> (); u = cin<U> (); v = cin<V> (); w = cin<W> (); x = cin<X> (); y = cin<Y> (); z = cin<Z> (); }
  public T[] cinarr<T> () { return Castarr<T> (Str.Split (' ')); }
}