#include<bits/stdc++.h>
#define rep(i,n)for(int i=0;i<n;i++)
using namespace std;

int h, w, sx, sy, gx, gy;
int mp[50][50];
bool flag[50][50];
int dx[]{ 1,-1,0,0 }, dy[]{ 0,0,1,-1 };
int dx2[]{ 2,-2,0,0 }, dy2[]{ 0,0,2,-2 };

void dfs(int x, int y) {
	flag[x][y] = true;
	rep(i, 4) {
		int nx = x + dy[i], ny = y + dx[i];
		if (0 <= nx&&nx < h && 0 <= ny&&ny < w && !flag[nx][ny] && abs(mp[x][y] - mp[nx][ny]) <= 1)
			dfs(nx, ny);
	}
	rep(i, 4) {
		int nx = x + dx2[i], ny = y + dy2[i];
		if (0 <= nx&&nx < h && 0 <= ny&&ny < w && !flag[nx][ny] && mp[x][y] == mp[nx][ny] && mp[x + dx2[i] / 2][y + dy2[i] / 2] < mp[x][y])
			dfs(nx, ny);
	}
}
int main() {
	scanf("%d%d%d%d%d%d", &h, &w, &sx, &sy, &gx, &gy);
	sx--; sy--; gx--; gy--;
	rep(i, h)rep(j, w)scanf("%1d", &mp[i][j]);
	dfs(sx, sy);
	puts(flag[gx][gy] ? "YES" : "NO");
}