#include <cstdio>

 #include <queue>

 #include <cstring>

 using namespace std;

 #define MAXN 1100

 int G[MAXN][MAXN], dist[MAXN*MAXN];

 const int dir[][] = {{-, }, {, -}, {, }, {, }};

 int main()

 {

 #ifdef LOCAL

     freopen("in", "r", stdin);

 #endif

     int R, C;

     while (scanf("%d%d", &R, &C) && (R || C))

     {

         int k;

         scanf("%d", &k);

         memset(G, , sizeof G);

         for (int i = ; i < k; i++)

         {

             int r, n;

             scanf("%d%d", &r, &n);

             for (int j = ; j < n; j++)

             {

                 int x;

                 scanf("%d", &x);

                 G[r][x] = ;

             }

         }

         int x, y;

         scanf("%d%d", &x, &y);

         int src = x*C + y;

         scanf("%d%d", &x, &y);

         int dest = x*C + y;

         queue<int> q;

         memset(dist, -, sizeof dist);

         q.push(src);

         dist[src] = ;

         while (!q.empty())

         {

             int u = q.front();

             q.pop();

             if (u == dest)  break;

             int x = u / C;

             int y = u % C;

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

             {

                 int dx = x + dir[i][], dy = y + dir[i][];

                 int v = dx * C + dy;

                 if (dx >=  && dx < R && dy >=  && dy < C && G[dx][dy] ==  && dist[v] == -)

                 {

                     dist[v] = dist[u] + ;

                     q.push(v);

                 }

             }

         }

         printf("%d\n", dist[dest]);

     }

     return ;

 }