#include <iostream>

#include <vector>

#include <memory.h>

#include <queue>

using namespace std;

const int nxt[4][2] = { {1, 0}, {-1, 0}, {0, 1}, {0, -1} };

int M[1002][1002];

int R, C;

int x_1, y_1, x_2, y_2;

int bfs()

{

    queue< pair<int, int> > Q;

    Q.push({ x_1, y_1 });

    M[x_1][y_1] = 1;

    while (!Q.empty())

    {

        auto [ux, uy] = Q.front();

        Q.pop();

        for (int i = 0; i < 4; ++i)

        {

            int vx = ux + nxt[i][0];

            int vy = uy + nxt[i][1];

            if (vx >= 0 && vy >= 0 && vx < R && vy < C && !M[vx][vy])

            {

                M[vx][vy] = M[ux][uy] + 1;

                if (vx == x_2 && vy == y_2) return M[vx][vy] - 1;

                Q.push({ vx, vy });

            }

        }

    }

    return -1;

}

int main()

{

    // fast io

    ios::sync_with_stdio(false);

    cin.tie(nullptr);

    cout.tie(nullptr);

    int N, r, k, c;

    while (cin >> R >> C, R && C)

    {

        memset(M, 0, sizeof(M));

        // build map

        cin >> N;

        while (N--)

        {

            cin >> r >> k;

            while (k--)

            {

                cin >> c;

                M[r][c] = 1;

            }

        }

        cin >> x_1 >> y_1 >> x_2 >> y_2;		

        cout << bfs() << "\n";

    }

    return 0;

}