#include<cstdio>
#include <iostream>
#include<algorithm>
#include<string>
#include<queue>
#include<vector>
#include<functional>
#include<cmath>
#include<map>
#include<stack>
#include<set>
#include<numeric>

#define mod 1000000007;

using namespace std;
typedef long long ll;
typedef pair<ll, ll> Pr;

int h, w;
int sx, sy, gx, gy;
int field[55][55];
int used[55][55];
bool flag = false;

int dx[] = { -1,0,1,0 }, dy[] = { 0,1,0,-1 };

int solve() {
	queue<Pr> q;

	q.push({ sy,sx });
	used[sx][sy] = 1;
	while (!q.empty()) {
		int x = q.front().first;
		int y = q.front().second; 
		q.pop();
		for (int i = 0; i < 4; i++) {
			int ddx = dx[i] + x, ddy = dy[i] + y;
			if (ddx >= 0 && ddx < w && ddy >= 0 && ddy < h ) {
				if (abs(field[y][x] - field[ddy][ddx] )<=1 && used[ddy][ddx] == 0) {
					used[ddy][ddx] = 1;
					//cout << "ddx1 = " << ddx << " ddy1 = " << ddy << " d = " << field[y][x] - field[ddy][ddx] << endl;
					q.push({ddx,ddy});
				}
				if (ddx + dx[i] >= 0 && ddx + dx[i] < w && ddy + dy[i] >= 0 && ddy + dy[i] < h
					&& used[ddy+dy[i]][ddx+dx[i]] == 0) {
					if (field[y][x] == field[ddy+dy[i]][ddx+dx[i]] && field[ddy][ddx] < field[y][x]) {
					//	cout << "ddx2 = " << ddx+dx[i] << " ddy2 = " << ddy+dy[i] << endl;
						used[ddy + dy[i]][ddx + dx[i]] = 1;
						q.push({ddx+dx[i],ddy+dy[i]});
					}
				}
			}
		}
	}
	return used[gx][gy];
}

 int main()
 { 
	 cin >> h >> w;
	 cin >> sx >> sy >> gx >> gy;
	 sx--, sy--, gx--, gy--;
	 for (int i = 0; i < h; i++) {
		 for (int j = 0; j < w; j++) {
			 scanf("%1d",&field[i][j]);
		 }
	 }
	
	 if (solve())cout << "YES" << endl;
	 else cout << "NO" << endl;
	return 0;
 }