#include <iostream>
#include <fstream>


using namespace std;


ifstream input_stream;
ofstream output_stream;


void runMarkdown(bool mx[][100], bool mk[][100], uint16_t nodeX, uint16_t nodeY, uint8_t N) {
	mk[nodeY][nodeX] = true;

	// Top
	if (nodeY - 1 >= 0 && mx[nodeY - 1][nodeX] && !mk[nodeY - 1][nodeX]) {
		runMarkdown(mx, mk, nodeX, nodeY - 1, N);
	}
	
	// Bottom
	if (nodeY + 1 < N && mx[nodeY + 1][nodeX] && !mk[nodeY + 1][nodeX]) {
		runMarkdown(mx, mk, nodeX, nodeY + 1, N);
	}

	// Left
	if (nodeX - 1 >= 0 && mx[nodeY][nodeX - 1] && !mk[nodeY][nodeX - 1]) {
		runMarkdown(mx, mk, nodeX - 1, nodeY, N);
	}
	
	// Right
	if (nodeX + 1 < N && mx[nodeY][nodeX + 1] && !mk[nodeY][nodeX + 1]) {
		runMarkdown(mx, mk, nodeX + 1, nodeY, N);
	}
}


int main() {
	input_stream.open("Insule.txt");
	output_stream.open("output.txt");

	uint16_t N;
	input_stream >> N;

	bool matrix[N][100];
	bool marks[N][100];

	for (uint8_t i = 0; i < N; i++) {
		for (uint8_t j = 0; j < N; j++) {
			input_stream >> matrix[i][j];
			marks[i][j] = 0;
		}
	}


	uint32_t total = 0;

	for (uint16_t i = 0; i < N; i++) {
		for (uint16_t j = 0; j < N; j++) {
			if (matrix[i][j] && !marks[i][j]) {
				runMarkdown(matrix, marks, j, i, N);
				total++;
			}
		}
	}

	// File method:
	// output_stream << total << endl;
	// Console method:
	cout << total << endl;

	input_stream.close();
	return 0;
}