#define _CRT_SECURE_NO_WARNINGS

#include <iostream>
#include <string>
#include <vector>
#include <cmath>
#include <fstream>
#include <set>
#include <utility>
#include <algorithm>
#include <queue>
#include <stack>
#include <deque>
#include <numeric>
#include <sstream>
#include <list>
#include <map>
#include <stdlib.h>
#include <time.h>

#define rep(i,p,n) for(int i=(int)p;i<(int)n;i++)
#define repp(i,p,n) for(int i=(int)p;i>=(int)n;i--)
#define Sort(x) sort(x.begin(),x.end());
#define ll long long
#define INF 2000000000

using namespace std;
int main() {
	int n;
	cin >> n;
	vector<int> v(n);
	rep(i, 0, n)cin >> v[i];
	Sort(v);

	int ans = 0;
	while (!v.empty()) {
		if (v[0] == v[1]) {
			v.erase(v.begin());
			v.erase(v.begin());
		}
		else {
			if (v.size() == 2) {
				ans += 2;
				v.erase(v.begin());
				break;
			}
			else {
				ans++;
				v.erase(v.begin());
			}
		}
	}
	cout << ans << endl;

	return 0;
}