#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
using namespace std;
void dfs(vector<vector<int>> &graph, int row, int col)
{
int n = graph.size();
// int area = 1;
graph[row][col] = 0;
// vector<int> direction = {-1, 0, 1, 0, -1};
// for (int i = 0; i < 4; ++ i) {
// int rowNew = row + direction[i];
// int colNew = col + direction[i + 1];
// if (rowNew >= 0 && rowNew < m && colNew >= 0 && colNew < n && graph[rowNew][colNew] == 1) {
// dfs(graph, rowNew, colNew);
// }
// }
int x = row;
int y = col;
for (int i = 0; i < n; ++i)
{
// for (int j = col; j < n; ++j) {
// if (graph[i][j] == 1 && i != j) {
// graph[i][j] = 0;
// dfs(graph, j, i);
// } else if (graph[i][j] == 1 && i == j) {
// graph[i][j] = 0;
// }
// }
if (graph[x][i] == 1 && x != i)
{
graph[x][i] = 0;
dfs(graph, i, x);
}
else if (graph[x][i] == 1 && x == i)
{
graph[x][i] = 0;
}
}
// return area;
}
int countArea(vector<vector<int>> &graph, int n)
{
int result = 0;
for (int i = 0; i < n; ++i)
{
for (int j = 0; j < n; ++j)
{
if (graph[i][j] == 1)
{
result++;
dfs(graph, i, j);
break;
}
}
}
return result;
}
int main()
{
int n;
cin >> n;
vector<vector<int>> graph(n, vector<int>(n));
for (int i = 0; i < n; ++i)
{
for (int j = 0; j < n; ++j)
{
cin >> graph[i][j];
}
}
cout << countArea(graph, n);
return 0;
}