#include <cstdio>
#include <cmath>

#define FOR( i, l, r) for(int i = (l)    ; i <  (r); i++)
#define FOR1(i, l, r) for(int i = (l)    ; i <= (r); i++)
#define REV( i, l, r) for(int i = (r) - 1; i >= (l); i--)
#define REV1(i, l, r) for(int i = (r)    ; i >= (l); i--)
#define INC( i, n) FOR( i, 0, n)
#define INC1(i, n) FOR1(i, 1, n)
#define DEC( i, n) REV( i, 0, n)
#define DEC1(i, n) REV1(i, 1, n)

typedef   signed long long int LL;
typedef unsigned long long int UL;

template<typename T> void swap(T &x, T &y) { T t = x; x = y; y = t; return; }
template<typename T> T abs(T x) { return (x > 0 ? x : -x); }
template<typename T> T max(T a, T b) { return (a > b ? a : b); }
template<typename T> T min(T a, T b) { return (a < b ? a : b); }
template<typename T> bool setmin(T &a, T b) { if(a <= b) { return false; } else { a = b; return true; } }
template<typename T> bool setmax(T &a, T b) { if(a >= b) { return false; } else { a = b; return true; } }
template<typename T> T gcd(T a, T b) { return (b == 0 ? a : gcd(b, a % b)); }
template<typename T> T lcm(T a, T b) { return a / gcd(a, b) * b; }

// ---- ----

int h, w, sx, sy, gx, gy;
char b[50][51];
int a[50][50];

int dx[8] = { 1, 0, -1,  0, 2, 0, -2,  0 };
int dy[8] = { 0, 1,  0, -1, 0, 2,  0, -2 };

void search(int x, int y) {
	a[x][y] = 1;
	
	INC(i, 8) {
		int xx = x + dx[i];
		int yy = y + dy[i];
		if(
			0 <= xx && xx < h &&
			0 <= yy && yy < w &&
			a[xx][yy] == 0 &&
			(
				(i <  4 && abs(b[x][y] - b[xx][yy]) <= 1) ||
				(i >= 4 && b[x][y] == b[xx][yy] && b[x][y] >= b[(x + xx) / 2][(y + yy) / 2])
			)
		) { search(xx, yy); }
	}
	
	return;
}

int main() {
	scanf("%d%d%d%d%d%d", &h, &w, &sx, &sy, &gx, &gy);
	INC(i, h) { scanf("%s", b[i]); }
	sx--; sy--; gx--; gy--;
	
	search(sx, sy);
	
	printf("%s\n", (a[gx][gy] ? "YES" : "NO"));
	
	return 0;
}