#include <iostream>
#include <string>
#include <algorithm>
#include <vector>
#include <stack>
#include <queue>
#include <list>
#include <set>
#include <map>
#include <numeric>
#include <regex>
#include <tuple>
#include<iomanip>
using namespace std;

typedef long long ll;
typedef pair<int, int> P;
#define MOD 1000000007 // 10^9 + 7
#define INF 1000000000 // 10^9
#define LLINF 1LL<<60

int H, W;
int level[59][59];
bool isfound[59][59];
int dx[4] = { 1,0,-1,0 };
int dy[4] = { 0,1,0,-1 };

bool isrange(int x, int y) {
	bool flag = true;
	if (x <= 0 || x > H) flag = false;
	if (y <= 0 || y > W) flag = false;
	return flag;
}

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);

	cin >> H >> W;
	P start, goal;
	cin >> start.first >> start.second >> goal.first >> goal.second;

	for (int i = 0; i < H; i++) {
		string S; cin >> S;
		for (int j = 0; j < W; j++) {
			level[i + 1][j + 1] = (S[j] - '0');
		}
	}


	queue<P> Q;
	isfound[start.first][start.second] = true;

	Q.push(start);
	while (!Q.empty()) {
		P cur = Q.front();
		Q.pop();
		int cx = cur.first;
		int cy = cur.second;

		for (int i = 0; i < 4; i++) {
			int nx = cx + dx[i];
			int ny = cy + dy[i];
			if (isrange(nx, ny)) {
				if (!isfound[nx][ny] && abs(level[cx][cy] - level[nx][ny]) <= 1) {
					isfound[nx][ny] = true;
					Q.push(P(nx,ny));
				}
			}
		}

		for (int i = 0; i < 4; i++) {
			int nx = cx + 2*dx[i];
			int ny = cy + 2*dy[i];
			if (isrange(nx, ny)) {
				if (!isfound[nx][ny] && level[cx][cy] == level[nx][ny] && level[cx][cy] > level[cx+dx[i]][cy+dy[i]]) {
					isfound[nx][ny] = true;
					Q.push(P(nx, ny));
				}
			}
		}
	}

	if (isfound[goal.first][goal.second]) cout << "YES" << endl;
	else cout << "NO" << endl;


	return 0;
}