#include <map>
#include <set>
#include <list>
#include <cmath>
#include <ctime>
#include <deque>
#include <queue>
#include <stack>
#include <bitset>
#include <cstdio>
#include <limits>
#include <vector>
#include <cstdlib>
#include <numeric>
#include <sstream>
#include <iostream>
#include <algorithm>
#include <functional> 
#include <iomanip>
#include <unordered_map>
#include <memory.h>
#include <unordered_set>
#include <fstream>

using namespace std;

int dy[4] = { -1,0,1,0 };
int dx[4] = { 0,1,0,-1 };
bool visited[51][51];
char board[51][51];
int sy, sx, gy, gx, h, w;

int main(void)
{
	cin.tie(0);
	ios::sync_with_stdio(false);
	
	cin >> h >> w;
	cin >> sy >> sx >> gy >> gx;
	for (int i = 1; i <= h; i++)
	{
		for (int j = 1; j <= w; j++)
		{
			cin >> board[i][j];
		}
	}

	memset(visited, false, sizeof(visited));
	visited[sy][sx] = true;
	queue <pair<int, int>> que;
	que.push({ sy,sx });

	while (!que.empty())
	{
		int y = que.front().first;
		int x = que.front().second;
		que.pop();

		for (int i = 0; i < 4; i++)
		{
			int ny = y + dy[i];
			int nx = x + dx[i];
			if (ny <= 0 || ny > h || nx <= 0 || nx > w)
			{
				continue;
			}
			if (abs(board[ny][nx] - board[y][x]) <= 1)
			{
				if (visited[ny][nx] == false)
				{
					visited[ny][nx] = true;
					que.push({ ny,nx });
				}
			}
		}
		for (int i = 0; i < 4; i++)
		{
			int ny = y + 2*dy[i];
			int nx = x + 2*dx[i];
			if (ny <= 0 || ny > h || nx <= 0 || nx > w)
			{
				continue;
			}
			int my = (ny + y) / 2;
			int mx = (nx + x) / 2;
			if (board[my][mx]<=board[y][x] && board[y][x]==board[ny][nx])
			{
				if (visited[ny][nx] == false)
				{
					visited[ny][nx] = true;
					que.push({ ny,nx });
				}
			}
		}
	}

	if (visited[gy][gx])
	{
		cout << "YES" << '\n';
	}
	else
	{
		cout << "NO" << '\n';
	}
	return 0;
}