import java.util.Hashtable;

public class GoogleChallenge3 {

    public int solution(String[] L) {
        Hashtable<String, Integer> map = new Hashtable<>();
        for (int i = 0; i < L.length; i++) {
            String key = getDomain(L[i]) + countLocalName(L[i], 0);
            if (!map.containsKey(key))
                map.put(key, 1);
            else
                map.put(key, map.get(key) + 1);
        }
        int result = 0;
        for (String s : map.keySet()) {
            if (map.get(s) > 1)
                result++;
        }
        return result;
    }

    private int countLocalName(String email, int i) {
        if (email.charAt(i) == '@' || email.charAt(i) == '+')
            return 0;
        if (email.charAt(i) == '.')
            return countLocalName(email, i + 1);
        return countLocalName(email, i + 1) + 1;
    }

    private String getDomain(String email) {
        return email.substring(email.indexOf('@'), email.length());
    }

    public static void main(String[] args) {
        int N = 7;
        String[] L = new String[N];
        L[0] = "a.b@example.com";
        L[1] = "x@example.com";
        L[2] = "x@exa.mple.com";
        L[3] = "ab+1@example.com";
        L[4] = "y@example.com";
        L[5] = "y@example.com";
        L[6] = "y@example.com";

        System.out.println(new GoogleChallenge3().solution(L));
    }

}