using System;

using System.Collections.Generic;

using System.Linq;

using System.Text.Json;

public class Program

{

    public static void Main()

    {

        var related = new List<string>

        {

            "1100",

            "1110",

            "0110",

            "0001"

        };

        Console.WriteLine(CountGroups(related));

    }

    public static int CountGroups(List<string> related) {

        var size = related.Count;

        var relations = new Dictionary<int, HashSet<int>>();

        for (var i = 0; i < size; i++) {

            for (var j = 0; j < size; j++) {

                if (related[i][j] == '1') {

                    if (!relations.ContainsKey(i)) {

                        relations[i] = new HashSet<int>();

                    }

                    if (!relations.ContainsKey(j)) {

                        relations[j] = new HashSet<int>();

                    }

                    relations[i].Add(j);

                    relations[j].Add(i);

                }

            }

        }

        var result = 0;

        foreach (var currentUser in relations.Keys) {

            var plain = PlainGroups(relations, currentUser);

            result += plain.Count > 0 ? 1 : 0;

        }

        return result;

    }

    public static HashSet<int> PlainGroups(Dictionary<int, HashSet<int>> relations, int currentUser) {

        HashSet<int> users = relations[currentUser];

        var nextUsers = users.ToList();

        var allUsers = new HashSet<int>(nextUsers);

        users.Clear();

        foreach (var nextUser in nextUsers) {

            var plain = PlainGroups(relations, nextUser);

            if (plain != null) {

                foreach (var p in plain) {

                    allUsers.Add(p);

                }

            }

        }

        return allUsers;

    }

}