#include <iostream> #include <iomanip> #include <vector> #include <algorithm> #include <utility> #include <string> #include <queue> #include <stack> #include <unordered_set> #include <unordered_map> using namespace std; typedef long long int ll; typedef pair<int, int> Pii; const ll mod = 998244353; int main() { cin.tie(0); ios::sync_with_stdio(false); int n; cin >> n; vector<int> a(n); for (auto &x: a) cin >> x; unordered_map<int, int> item_counts; for (auto &x: a) { item_counts[x]++; } int ans = 0; for (auto &[k, v]: item_counts) { ans += v / 2; } cout << ans << endl; return 0; }