import sys
sys.setrecursionlimit(9**9)
h,w=map(int,input().split())
sy,sx,gy,gx=map(int,input().split())
sx-=1
sy-=1
gx-=1
gy-=1
b=[list(map(int,input()))for _ in[0]*h]
c=[[False]*w for _ in[0]*h]
c[sy][sx]=True
def s(x,y):
	for i in[(1,0),(-1,0),(0,1),(0,-1)]:
		if 0<=x+i[0]<w and 0<=y+i[1]<h and c[y+i[1]][x+i[0]]==False and abs(b[y+i[1]][x+i[0]]-b[y][x])<2:
			c[y+i[1]][x+i[0]]=True
			s(x+i[0],y+i[1])
	for i in[(2,0),(-2,0),(0,2),(0,-2)]:
		if 0<=x+i[0]<w and 0<=y+i[1]<h and c[y+i[1]][x+i[0]]==False and b[y+i[1]//2][x+i[0]//2]<b[y+i[1]][x+i[0]]==b[y][x]:
			c[y+i[1]][x+i[0]]=True
			s(x+i[0],y+i[1])
s(sx,sy)
print(["NO","YES"][c[gy][gx]])