import java.util.Arrays;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.Scanner;
import java.util.Set;

public class Main {
	
	public static int[][] move_dirs = {
		{0,  1},
		{0, -1},
		{ 1, 0},
		{-1, 0}
	};
	
	public static boolean in_range(int x, int y, int w, int h){
		return 0 <= x && x < w && 0 <= y && y < h;
	}
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		
		final int h = sc.nextInt();
		final int w = sc.nextInt();
		
		final int sy = sc.nextInt() - 1;
		final int sx = sc.nextInt() - 1;
		final int gy = sc.nextInt() - 1;
		final int gx = sc.nextInt() - 1;
		
		int[][] heights = new int[h][w];
		
		for(int i = 0; i < h; i++){
			final char[] in = sc.next().toCharArray();
			
			for(int j = 0; j < w; j++){
				heights[i][j] = Character.getNumericValue(in[j]);
			}
		}
		
		boolean[][] visited = new boolean[h][w];
		
		LinkedList<Integer> x_queue = new LinkedList<Integer>();
		LinkedList<Integer> y_queue = new LinkedList<Integer>();
		x_queue.add(sx); y_queue.add(sy);
		visited[sy][sx] = true;
		
		while(!x_queue.isEmpty()){
			final int x = x_queue.poll();
			final int y = y_queue.poll();
			
			for(int[] move : move_dirs){
				final int nx = x + move[0];
				final int ny = y + move[1];
				final int nnx = x + move[0] * 2;
				final int nny = y + move[1] * 2;
				
				if(!in_range(nx, ny, w, h)){
					continue;
				}
				
				if(!visited[ny][nx] && Math.abs(heights[y][x] - heights[ny][nx]) <= 1){
					visited[ny][nx] = true;
					x_queue.add(nx); y_queue.add(ny);
				}
				
				if(!in_range(nnx, nny, w, h)){
					continue;
				}
				
				if(!visited[nny][nnx] && heights[nny][nnx] == heights[y][x] && heights[ny][nx] < heights[y][x]){
					visited[nny][nnx] = true;
					x_queue.add(nnx); y_queue.add(nny);
				}
			}
		}
		
		System.out.println(visited[gy][gx] ? "YES" : "NO");
	}

}