#include <iostream>

#include <string>

#include <sstream>

#include <vector>

using namespace std;

int main()

{

	// fast io

	ios::sync_with_stdio(false);

	cin.tie(nullptr);

	cout.tie(nullptr);

	int N, v, u, a, b;

	string str;

	vector<int> g1[101], g2[101];

	while (cin >> N, N)

	{

		// init

		cin.ignore();

		for (int i = 1; i <= N; ++i)

		{

			g1[i].assign(N + 1, 101);

			g2[i].assign(N + 1, 101);

		}

		// store graph

		for (int i = 1; i <= N * 2; ++i)

		{

			getline(cin, str);

			stringstream ss(str);

			ss >> u;

			while (ss >> v) i <= N ? g1[u][v] = 1 : g2[u][v] = 1;

		}

		// Floyd-Warshall algorithm

		for (int k = 1; k <= N; ++k)

		{

			for (int i = 1; i <= N; ++i) for (int j = 1; j <= N; ++j)

			{

				g1[i][j] = min(g1[i][j], g1[i][k] + g1[k][j]);

				g2[i][j] = min(g2[i][j], g2[i][k] + g2[k][j]);

			}

		}

		cin >> a >> b;

		bool out = false;

		for (int i = 1; i <= N && !out; ++i) for (int j = 1; j <= N && !out; ++j)

		{

			if (i == j) continue;

			if (g2[i][j] > g1[i][j] * a + b) out = true;

		}

		cout << (out ? "No" : "Yes") << "\n";

	}

	return 0;

}