import java.util.Scanner;
import static java.lang.System.*;
import java.util.ArrayList;
public class Main {
public static void main(String[] args) {
Scanner scan = new Scanner(in);
int n = scan.nextInt();
ArrayList<Integer> cs = new ArrayList<>();
for (int i = 0; i < n; ++i) {
int c = scan.nextInt();
cs.add(c);
}
ArrayList<Integer> fs = new ArrayList<>();
int r = 0;
for (int i = 0; i < n; ++i) {
if (fs.indexOf(cs.get(i)) >= 0) {
continue;
}
int g = 0;
for (int j = 0; j < n; ++j) {
if (cs.get(i) == cs.get(j)) ++g;
}
r += g / 2;
fs.add(cs.get(i));
}
out.println(r);
}
}
