import sys
input=lambda: sys.stdin.readline().rstrip()
h,w=map(int,input().split())
sx,sy,gx,gy=map(int,input().split())
B=[input() for _ in range(h)]
n=h*w
d=((1,0),(0,1),(-1,0),(0,-1))

par=[-1]*n

def find(x):
  if par[x]<0:
    return x
  else:
    par[x]=find(par[x])
    return par[x]

def unite(x,y):
  x=find(x)
  y=find(y)
  if x==y:
    return False
  else:
    if par[x]>par[y]:
      x,y=y,x
    par[x]+=par[y]
    par[y]=x
    return True

def same(x,y):
  return find(x)==find(y)

def size(x):
  return -par[find(x)]

for i in range(h):
  for j in range(w):
    cur=int(B[i][j])
    for dx,dy in d:
      if 0<=i+dx<h and 0<=j+dy<w:
        if abs(cur-int(B[i+dx][j+dy]))<=1:
          unite(i*w+j,(i+dx)*w+j+dy)
    for dx,dy in d:
      if 0<=i+2*dx<h and 0<=j+2*dy<w:
        if cur==int(B[i+2*dx][j+2*dy]) and int(B[i+dx][j+dy])<cur:
          unite(i*w+j,(i+2*dx)*w+j+2*dy)


if same((sx-1)*w+sy-1,(gx-1)*w+gy-1):
  print("YES")
else:
  print("NO")