using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Pair = System.Collections.Generic.KeyValuePair<int, int>;
//key = x, value = y

namespace yuki_424
{
    class Program
    {
        static int h, w;
        static int sx, sy, gx, gy;
        static int[] dx = { -1, 1, 0, 0, -2, 2, 0, 0 };
        static int[] dy = { 0, 0, -1, 1, 0, 0, -2, 2 };
        static void Main(string[] args)
        {
            var t = scan;
            h = t[0]; w = t[1];
            t = scan;
            sx = t[0]-1;sy = t[1]-1;gx = t[2]-1;gy = t[3]-1;

            var M = new Dictionary<Pair, int>();
            var N = new HashSet<Pair>();
            for (int i = 0; i < h; i++)
            {
                string s = Console.ReadLine();
                for (int j = 0; j < w; j++)
                {
                    M[new Pair(i, j)] = int.Parse(s[j].ToString());
                }
            }
          

            
            var Q = new Queue<Pair>();
            Q.Enqueue(new Pair(sx, sy));
            N.Add(new Pair(sx, sy));

            bool flag = false;
            while (Q.Any())
            {
                var u = Q.Dequeue();
                //Console.WriteLine(u.Key+" "+u.Value);
                if(u.Key == gx && u.Value == gy)
                {
                    flag = true;
                    break;
                }
                for (int i = 0; i < 4; i++)
                {
                    var tx = u.Key + dx[i];
                    var ty = u.Value + dy[i];
                    if (tx < 0 || ty < 0 || tx >= h || ty >= w) continue;
                    var p = new Pair(tx, ty);
                    if (Math.Abs(M[p] - M[u]) <= 1 && !N.Contains(p))
                    {
                        Q.Enqueue(p);
                        N.Add(p);
                    }
                }
                for (int i = 4; i < 8; i++)
                {
                    var tx = u.Key + dx[i];
                    var ty = u.Value + dy[i];
                    if (tx < 0 || ty < 0 || tx >= h || ty >= w) continue;
                    var p = new Pair(tx, ty);
                    var s = new Pair((tx + u.Key) / 2, (ty + u.Value) / 2);
                    if (M[p] == M[u] && !N.Contains(p) && M[s] < M[u])
                    {
                        Q.Enqueue(p);
                        N.Add(p);
                    }
                }

            }
            if (flag) Console.WriteLine("YES");
            else Console.WriteLine("NO");
        }

        static int[] scan { get { return Array.ConvertAll(Console.ReadLine().Split(), int.Parse); } }
    }
}