import java.io.*;
import java.util.*;
class Main {
    public static void main(String args[]) throws IOException {
        BufferedReader read = new BufferedReader(new InputStreamReader(System.in));
        int N = Integer.parseInt(read.readLine());

        ArrayList<ArrayList<Integer>> adj = new ArrayList<>();

        for(int i=0; i<N; i++)
        {
            String S[] = read.readLine().split(" ");
            ArrayList<Integer> temp = new ArrayList<>();
            for(int j=0; j<N; j++)
                temp.add(Integer.parseInt(S[j]));
            adj.add(temp);
        }

        Solution ob = new Solution();
        System.out.println(ob.components(adj,N));
    }
}

class Solution {
     void dfs(ArrayList<ArrayList<Integer>> M, int[] visited, int i)
    {
        for (int j = 0; j < M.size(); j++)
        {
            if (i!=j && M.get(i).get(j) == 1 && visited[j] == 0)
            {
                visited[j] = 1;
                dfs(M, visited, j);
            }
        }
    }

    int components(ArrayList<ArrayList<Integer>> adj, int N) {

        int[] visited = new int[adj.size()];
        int count = 0;
        for (int i = 0; i < adj.size(); i++)
        {
            if (visited[i] == 0)
            {
                dfs(adj, visited, i);
                count++;
            }
        }
        return count;
    }
};