#include <iostream>
#include <vector>
using namespace std;

void dfs(int v, vector<vector<int>>& graph, vector<int>& colors) {
	colors[v] = 1;
	for (int i = 0; i < graph.size(); i++) {
		if (graph[v][i] == 1 && colors[i] == 0) {
			dfs(i, graph, colors);
		}
	}
	colors[v] = 2;
}

int main() {
	int n;
	int k;
	cin >> n >> k;
	k--;
	
	vector<vector<int>> graph(n, vector<int>(n));
	for (auto& row : graph) {
		for (auto& elem : row) {
			cin >> elem;
		}
	}
	vector<int> colors(n);
	dfs(k, graph, colors);
	
	int ans = 0;
	for (int& color : colors) {
		if (color == 2) {
			ans++;
		}
	}
	cout << ans;
	
	return 0;
}