import Queue

h,w = map(int, raw_input().split())
sx,sy,gx,gy = map(int, raw_input().split())
sx-=1
sy-=1
gx-=1
gy-=1
dist = [[0,1], [0,-1], [1,0], [-1,0]]
blocks = [[0]*w for _ in xrange(h)]
checked = [[False]*w for _ in xrange(h)]
for i in xrange(h):
  b = raw_input()
  for j in xrange(w):
    blocks[i][j] = int(b[j])
q = Queue.Queue()
q.put([sx, sy])
checked[sx][sy] = True

reach = False
counter = 0
while q.qsize() > 0:
  counter += 1
  pos = q.get()
  if pos[0]==gx and pos[1]==gy:
    reach = True
    break
  for d in dist:
    x = pos[0]+d[0]
    y = pos[1]+d[1]
    if x<0 or y<0 or h<=x or w<=y or checked[x][y]: continue
    if abs(blocks[pos[0]][pos[1]]-blocks[x][y]) <= 1 and checked[x][y]==False:
      q.put([x, y])
      checked[x][y] = True
  for d in dist:
    x = pos[0]+d[0]*2
    y = pos[1]+d[1]*2
    if x<0 or y<0 or h<=x or w<=y or checked[x][y]: continue
    if blocks[pos[0]][pos[1]] == blocks[x][y] and blocks[x][y] > blocks[x-d[0]][y-d[1]] and checked[x][y]==False:
      q.put([x, y])
      checked[x][y] = True

if reach: print "YES"
else: print "NO"