using System;
using System.IO;
using System.Linq;
using System.Text;
using System.Collections.Generic;
using System.Diagnostics;
using System.Numerics;
using Enu = System.Linq.Enumerable;

class Program
{
    static readonly string Impossible = "Odekakedekinai..";

    public void Solve()
    {
        int W = Reader.Int(), H = Reader.Int(), N = Reader.Int();
        var table = Reader.IntTable(N * 2);
        //var dij = new Dijkstra(H * W);
        var G = new List<Edge>[H * W];
        for (int i = 0; i < G.Length; i++)
            G[i] = new List<Edge>();

        for (int ti = 1; ti < N * 2; ti += 2)
        {
            var t = table[ti];
            for (int i = 0; i + 1 < t.Length; i++)
            {
                int r = t[i] / W, c = t[i] % W;
                int nr = t[i + 1] / W, nc = t[i + 1] % W;
                int dr = Math.Sign(nr - r), dc = Math.Sign(nc - c);
                for (; r != nr || c != nc; r += dr, c += dc)
                {
                    G[r * W + c].Add(new Edge((r + dr) * W + (c + dc), 1));
                    G[(r + dr) * W + (c + dc)].Add(new Edge(r * W + c, 1));
                }
            }
        }
        int ans = ShortestPath(0, G).Last();
        Console.WriteLine(ans == INF ? Impossible : ans + "");
    }

    static readonly int INF = (int)1e9;
    static int[] ShortestPath(int start, List<Edge>[] G)
    {
        int N = G.Length;
        bool[] inQue = new bool[N];
        var que = new Queue<int>();
        que.Enqueue(start);
        var minCost = new int[N];
        for (int i = 0; i < N; i++) minCost[i] = INF;
        minCost[start] = 0;

        while (que.Count > 0)
        {
            int v = que.Dequeue();
            inQue[v] = false;
            foreach (var e in G[v])
                if (minCost[v] + e.cost < minCost[e.to])
                {
                    minCost[e.to] = minCost[v] + e.cost;
                    if (!inQue[e.to])
                    {
                        inQue[e.to] = true;
                        que.Enqueue(e.to);
                    }
                }
        }
        return minCost;
    }

    struct Edge
    {
        public int to;
        public int cost;
        public Edge(int to, int cost) { this.to = to; this.cost = cost; }
    }
}


class Entry { static void Main() { new Program().Solve(); } }
class Reader
{
    private static TextReader reader = Console.In;
    private static readonly char[] separator = { ' ' };
    private static readonly StringSplitOptions op = StringSplitOptions.RemoveEmptyEntries;
    private static string[] A = new string[0];
    private static int i;
    private static void Init() { A = new string[0]; }
    public static void Set(TextReader r) { reader = r; Init(); }
    public static void Set(string file) { reader = new StreamReader(file); Init(); }
    public static bool HasNext() { return CheckNext(); }
    public static string String() { return Next(); }
    public static int Int() { return int.Parse(Next()); }
    public static long Long() { return long.Parse(Next()); }
    public static double Double() { return double.Parse(Next()); }
    public static int[] IntLine() { return Array.ConvertAll(Split(Line()), int.Parse); }
    public static int[] IntArray(int N) { return Enu.Range(0, N).Select(i => Int()).ToArray(); }
    public static int[][] IntTable(int H) { return Enu.Range(0, H).Select(i => IntLine()).ToArray(); }
    public static string[] StringArray(int N) { return Enu.Range(0, N).Select(i => Next()).ToArray(); }
    public static string Line() { return reader.ReadLine().Trim(); }
    private static string[] Split(string s) { return s.Split(separator, op); }
    private static string Next() { CheckNext(); return A[i++]; }
    private static bool CheckNext()
    {
        if (i < A.Length) return true;
        string line = reader.ReadLine();
        if (line == null) return false;
        if (line == "") return CheckNext();
        A = Split(line);
        i = 0;
        return true;
    }
}