#include <iostream>
using namespace std;

string b[50];
int h, w, sx, sy, gx, gy, dd[] = {1, 0, -1, 0, 1};
bool visited[50][50];

bool inside(int x, int y){ return 0 <= x && x < h && 0 <= y && y < w;}

bool solve(int x, int y){
	if(gx == x && y == gy) return true;
	if(visited[x][y]) return false;
	bool f = false;
	visited[x][y] = true;
	for(int i = 0; i < 4; i++){
		int nx = x + dd[i], ny = y + dd[i + 1];
		if(inside(nx, ny) && (b[x][y] == b[nx][ny] || b[x][y] == b[nx][ny] + 1 || b[x][y] == b[nx][ny] - 1)) f |= solve(nx, ny);
		int nx2 = x + 2 * dd[i], ny2 = y + 2 * dd[i + 1];
		if(inside(nx2, ny2) && b[x][y] == b[nx2][ny2] && b[x][y] > b[nx][ny]) f |= solve(nx2, ny2);
	}
	return f;
}

int main(){
	cin >> h >> w >> sx >> sy >> gx >> gy;
	for(int i = 0;i < h;i++) cin >> b[i];
	sx--; sy--; gx--; gy--;
	cout << (solve(sx, sy) ? "YES" : "NO") << endl;
}