#include <cstdio>
#include <algorithm>

#define rep(i, n) for(int i = 0; i < (n); ++i)

using namespace std;

const int dx[] = {-1, 0, 0, 1};
const int dy[] = {0, -1, 1, 0};

int n, m, sx, sy, gx, gy;
char x[50][51];
bool d[50][50];

bool range(int a, int b){
	return  0 <= a && a < n && 0 <= b &&  b < m;
}

void dfs(int a, int b){
	rep(i, 4){
		int p = dx[i], q = dy[i];
		if(range(a + p, b + q) && !d[a + p][b + q] && abs(x[a + p][b + q] - x[a][b]) <= 1){
			d[a + p][b + q] = true;
			dfs(a + p, b + q);
		}
		if(range(a + p * 2, b + q * 2) && !d[a + p * 2][b + q * 2] && x[a + p][b + q] < x[a][b] && x[a + p * 2][b + q * 2] == x[a][b]){
			d[a + p * 2][b + q * 2] = true;
			dfs(a + p * 2, b + q * 2);
		}
	}
}

int main(){
	scanf("%d%d%d%d%d%d", &n, &m, &sx, &sy, &gx, &gy);
	--sx; --sy; --gx; --gy;
	rep(i, n){
		scanf("%s", x[i]);
		rep(j, m){
			x[i][j] -= '0';
		}
	}

	d[sx][sy] = true;
	dfs(sx, sy);
	printf("%s\n", d[gx][gy] ? "YES" : "NO");
	return 0;
}