#include <algorithm>
#include <cstdio>
#include <iostream>
#include <map>
#include <math.h>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <string.h>
#include <vector>
using namespace std;

#define ll long long
#define INF (1 << 30)
#define INFLL (1LL << 60)

#define FOR(i,a,b) for(ll i = (a);i<(b);i++)
#define REP(i,a) FOR(i,0,(a))
#define MP make_pair

int h, w;
int sx, sy, gx, gy;
int hyo[51][51] = {};

int DIRX[4] = {1, -1, 0, 0};
int DIRY[4] = {0, 0, 1, -1};
int DIRX2[4] = {2, -2, 0, 0};
int DIRY2[4] = {0, 0, 2, -2};

bool check(int nowx, int nowy){
	if(nowx < 0 || nowy < 0 || nowy >= h || nowx >= w) return true;
	return false;
}

bool solve(){
	queue<pair<int, int> > que;
	que.push(MP(sx, sy));
	bool used[51][51] = {};
	while(que.size()){
		pair<int, int> data = que.front();que.pop();
		int nowx = data.first;
		int nowy = data.second;


		if(used[nowx][nowy]) continue;
		used[nowx][nowy] = true;
		// cout << nowx << "," << nowy << endl;

		if(nowx == gx && nowy == gy){
			return true;
		}

		for(int i = 0;i < 4;i++){
			int tox = nowx + DIRX[i], toy = nowy + DIRY[i];
			if(check(tox, toy)) continue;
			if(abs(hyo[nowx][nowy] - hyo[tox][toy]) > 1) continue;
			// if(nowx == sx && nowy == sy){
			// 	cout << tox << "," << toy << "-" << hyo[nowx][nowy] << endl;
			// }
			que.push(MP(tox, toy));
		}

		for(int i = 0;i < 4;i++){
			int tox = nowx + DIRX2[i], toy = nowy + DIRY2[i];
			int midx = nowx + DIRX[i], midy = nowy + DIRY[i];
			if(check(tox, toy)) continue;
			if(hyo[nowx][nowy] != hyo[tox][toy]) continue;
			if(hyo[midx][midy] > hyo[tox][toy]) continue;
			que.push(MP(tox, toy));
		}
	}

	return false;
}

int main() {
	cin >> h >> w;
	cin >> sy >> sx >> gy >> gx;
	sx--;gx--;sy--;gy--;
	string str;
	for(int i = 0;i < h;i++){
		cin >> str;
		for(int j = 0;j < str.size();j++){
			hyo[j][i] = str[j] - '0';
		}
	}
	// cout << sx << "--" << sy << endl;
	// cout << hyo[1][3] << endl;

	// cout << "--------------" << endl;
	// for(int i = 0;i < h;i++){
	// 	for(int j = 0;j < w;j++){
	// 		cout << hyo[j][i];
	// 	}
	// 	cout << endl;
	// }

	bool ans = solve();
	if(ans) cout << "YES" << endl;
	else cout << "NO" << endl;
	return 0;
}