import java.util.HashMap;
import java.util.Scanner;
public class KentBuggen {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
int nameCount = Integer.valueOf(scan.nextLine());
HashMap<String, Boolean> checkDB = new HashMap<String, Boolean>();
int dubs = 0;
for (int i = 0; i < nameCount; i++) {
String name = scan.nextLine();
if (!checkDB.containsKey(name)) {
checkDB.put(name, false);
} else if (!checkDB.get(name)) {
dubs++;
checkDB.put(name, true);
}
}
System.out.println(dubs);
scan.close();
}
}