#include <vector>
#include <string>
#include <cstdlib>
#include <iostream>
using namespace std;

void check(int h, int w, int cx, int cy, int gx, int gy, bool& possible, vector<vector<int>>& visited, vector<string>& maze) {
	if (cx == gx && cy == gy) {
		possible = true; return;
	}
	// cout << cx << " " << cy << endl;
	visited[cx - 1][cy - 1] = 1;
	
	if (cx < h && abs(maze[cx - 1][cy - 1] - maze[cx][cy - 1]) <= 1 && !visited[cx][cy - 1]) {
		check(h, w, cx + 1, cy, gx, gy, possible, visited, maze); 
	}
	if (cx > 1 && abs(maze[cx - 1][cy - 1] - maze[cx - 2][cy - 1]) <= 1 && !visited[cx - 2][cy - 1]) {
		check(h, w, cx - 1, cy, gx, gy, possible, visited, maze); 
	}
	if (cy < w && abs(maze[cx - 1][cy - 1] - maze[cx - 1][cy]) <= 1 && !visited[cx - 1][cy]) {
		check(h, w, cx, cy + 1, gx, gy, possible, visited, maze); 
	}
	if (cy > 1 && abs(maze[cx - 1][cy - 1] - maze[cx - 1][cy - 2]) <= 1 && !visited[cx - 1][cy - 2]) {
		check(h, w, cx, cy - 1, gx, gy, possible, visited, maze); 
	}
	if (cx < h - 1 && maze[cx - 1][cy - 1] > maze[cx][cy - 1] && maze[cx - 1][cy - 1] == maze[cx + 1][cy - 1] && !visited[cx + 1][cy - 1]) {
		check(h, w, cx + 2, cy, gx, gy, possible, visited, maze); 
	}
	if (cx > 2 && maze[cx - 1][cy - 1] > maze[cx - 2][cy - 1] && maze[cx - 1][cy - 1] == maze[cx - 3][cy - 1] && !visited[cx - 3][cy - 1]) {
		check(h, w, cx - 2, cy, gx, gy, possible, visited, maze); 
	}
	if (cy < w - 1 && maze[cx - 1][cy - 1] > maze[cx - 1][cy] && maze[cx - 1][cy - 1] == maze[cx - 1][cy + 1] && !visited[cx - 1][cy + 1]) {
		check(h, w, cx, cy + 2, gx, gy, possible, visited, maze); 
	}
	if (cy > 2 && maze[cx - 1][cy - 1] > maze[cx - 1][cy - 2] && maze[cx - 1][cy - 1] == maze[cx - 1][cy - 3] && !visited[cx - 1][cy - 3]) {
		check(h, w, cx, cy - 2, gx, gy, possible, visited, maze); 
	}

}


int main() {
	int h, w, sx, sy, gx, gy;
	cin >> h >> w >> sx >> sy >> gx >> gy;
	vector<vector<int>> visited (h, vector<int> (w, 0));
	vector<string> maze(h);
	for (int i = 0; i < h; i++) {
		cin >> maze[i];
	}
	bool possible = false;
	check(h, w, sx, sy, gx, gy, possible, visited, maze);
	if (possible) {
		cout << "YES" << endl;
	} else {
		cout << "NO" << endl;
	}
	return 0;
}