import collections
H,W = map(int,input().split())
sx,sy,gx,gy = map(int,input().split())
sx -= 1
sy -= 1
gx -= 1
gy -= 1
lshw = [list(map(int,list(input()))) for i in range(H)]
d = collections.deque([(sx,sy)])
used = [[False]*W for i in range(H)]

dxy = [(1,0),(-1,0),(0,1),(0,-1)]
dxy2 = [(2,0),(-2,0),(0,2),(0,-2)]
while d:
    x,y = d.popleft()
    if used[x][y]:
        continue
    used[x][y] = True
    for dx,dy in dxy:
        if 0 <= x+dx < H and 0 <= y+dy < W:
            if used[x+dx][y+dy]:
                continue
            if abs(lshw[x][y]-lshw[x+dx][y+dy]) <= 1:
                d.append((x+dx,y+dy))
    for k in range(4):
        dx2,dy2 = dxy2[k]
        dx,dy = dxy[k]
        if 0 <= x+dx2 < H and 0 <= y+dy2 < W:
            if used[x+dx2][y+dy2]:
                continue
            if lshw[x][y] == lshw[x+dx2][y+dy2] and lshw[x][y] > lshw[x+dx][y+dy]:
                d.append((x+dx2,y+dy2))
if used[gx][gy]:
    print('YES')
else:
    print('NO')