using System;
using System.Collections.Generic;
using System.Linq;

class Program {
    static int ReadInt() { return int.Parse(Console.ReadLine()); }
    static int[] ReadInts() { return Console.ReadLine().Split().Select(int.Parse).ToArray(); }
    static string[] ReadStrings() { return Console.ReadLine().Split(); }

    struct D {
        public int r;
        public int c;
    }

    static bool Calc(int srow, int scol, int grow, int gcol, int[,] g) {
        int rows = g.GetLength(0);
        int cols = g.GetLength(1);

        Func<int, int, bool> inRange = (r, c) => 0 <= r && r < rows && 0 <= c && c < cols;

        var delta = new[,] { { 1, 0 }, { -1, 0 }, { 0, 1 }, { 0, -1 } };

        var used = new bool[rows, cols];
        var q = new Queue<D>();
        q.Enqueue(new D { r = srow-1, c = scol-1 });
        while (q.Count > 0) {
            var d = q.Dequeue();

            if (d.r == grow-1 && d.c == gcol-1) return true;
            if (used[d.r, d.c]) continue;
            used[d.r, d.c] = true;

            for (int i = 0; i < 4; i++) {
                int r = d.r + delta[i, 0];
                int c = d.c + delta[i, 1];
                if (inRange(r, c) && Math.Abs(g[r, c] - g[d.r, d.c]) <= 1) {
                    q.Enqueue(new D { r = r, c = c });
                }

                // 2 つ先のブロックに移動する
                if (inRange(r, c) && g[d.r, d.c] > g[r, c]) {
                    int r2 = d.r + delta[i, 0] * 2;
                    int c2 = d.c + delta[i, 1] * 2;
                    if (inRange(r2, c2) && g[r2, c2] == g[d.r, d.c]) {
                        q.Enqueue(new D { r = r2, c = c2 });
                    }
                }
            }
        }
        return false;
    }

    static void Main() {
        var hw = ReadInts();
        var xs = ReadInts();

        int rows = hw[0], cols = hw[1];
        int srow = xs[0], scol = xs[1], grow = xs[2], gcol = xs[3];
        var g = new int[rows, cols];
        for (int i = 0; i < rows; i++) {
            var s = Console.ReadLine();
            for (int j = 0; j < cols; j++) {
                g[i, j] = s[j] - '0';
            }
        }

        Console.WriteLine(Calc(srow, scol, grow, gcol, g) ? "YES" : "NO");
    }
}