#include "vector"
#include "iostream"
using namespace std;

struct five {
	int minute, x0, y0, x1, y1;
};

inline bool check(five f1, five f2) {
	int t1 = f1.minute +
			abs(f1.x0 - f1.x1) +
			abs(f1.y0 - f1.y1);
	int dt = abs(f1.x1 - f2.x0) +
			abs(f1.y1 - f2.y0);
	return t1 + dt < f2.minute;
}

vector<vector<int>> g;
vector<int> pairs;
vector<char> used;
int cnt = 0;
bool dfs_kuhn(int v) {
	if (used[v])
		return false;
	used[v] = true;
	for (int to : g[v]) {
		if(pairs[to] == -1)
			cnt++;
		if (pairs[to] == -1 || dfs_kuhn(pairs[to])) {
			pairs[to] = v;
			return true;
		}
	}
	return false;
}

int main() {
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);
	int M;

	vector<five> ords;

	cin >> M;
	g.resize(M);

	for (int i = 0; i < M; ++i) {
		int h, m, x0, y0, x1, y1;
		char c;
		cin >> h >> c >> m >> x0 >> y0 >> x1 >> y1;
		five f = {h * 60 + m, x0, y0, x1, y1};
		for (int i = 0; i < ords.size(); ++i) {
			if (check(ords[i], f)){
				g[i].push_back(ords.size());
			}
		}
		ords.push_back(f);
	}

	pairs.assign(M, -1);
	for(int v = 0; v < M; ++v) {
		used.assign(M, false);
		dfs_kuhn(v);
	}

	cout << M - cnt << '\n';

	return 0;
}