import java.util.ArrayList;
import java.util.Scanner;

public class Main {
	static Scanner sc = new Scanner(System.in);
	static int[] DX = { 1, 0, -1, 0 };
	static int[] DY = { 0, 1, 0, -1 };

	public static void main(String[] args) {
		int H = sc.nextInt();
		int W = sc.nextInt();
		int SX = sc.nextInt() - 1;
		int SY = sc.nextInt() - 1;
		int GX = sc.nextInt() - 1;
		int GY = sc.nextInt() - 1;
		int[][] B = new int[H][W];
		for (int i = 0; i < H; ++i) {
			char[] row = sc.next().toCharArray();
			for (int j = 0; j < W; ++j) {
				B[i][j] = row[j] - '0';
			}
		}
		boolean[][] visited = new boolean[H][W];
		visited[SX][SY] = true;
		ArrayList<Integer> q = new ArrayList<>();
		q.add((SX << 16) | SY);
		for (int i = 0; i < q.size(); ++i) {
			int cx = q.get(i) >> 16;
			int cy = q.get(i) & 0xFFFF;
			if (GX == cx && GY == cy) {
				System.out.println("YES");
				return;
			}
			for (int j = 0; j < 4; ++j) {
				int nx = cx + DX[j];
				int ny = cy + DY[j];
				if (nx < 0 || H <= nx || ny < 0 || W <= ny) continue;
				if (visited[nx][ny]) continue;
				if (Math.abs(B[cx][cy] - B[nx][ny]) <= 1) {
					visited[nx][ny] = true;
					q.add((nx << 16) | ny);
				}
			}
			for (int j = 0; j < 4; ++j) {
				int nx = cx + DX[j] * 2;
				int ny = cy + DY[j] * 2;
				if (nx < 0 || H <= nx || ny < 0 || W <= ny) continue;
				if (visited[nx][ny]) continue;
				if (B[cx][cy] == B[nx][ny] && B[cx][cy] > B[cx + DX[j]][cy + DY[j]]) {
					visited[nx][ny] = true;
					q.add((nx << 16) | ny);
				}
			}
		}
		System.out.println("NO");
	}
}