from collections import deque
H, W = map(int, input().split())
sy, sx, gy, gx = map(int, input().split())
inf = float("inf")
b = [[inf]+list(map(int, input()))+[inf] for _ in [0]*H]
b = [[inf]*(W+2)] + b + [[inf]*(W+2)]

visited = [[0]*(W+2) for _ in [0]*(H+2)]
visited[sy][sx] = 1
dq = deque([(sx, sy, b[sy][sx])])
popleft, append = dq.popleft, dq.append
while dq:
    x, y, h = popleft()
    if x == gx and y == gy:
        print("YES")
        exit()
    for dx, dy in ((0, -1), (1, 0), (0, 1), (-1, 0)):
        nx, ny = x+dx, y+dy
        h2 = b[ny][nx]
        if abs(h-h2) <= 1 and visited[ny][nx] == 0:
            visited[ny][nx] = 1
            append((nx, ny, h2))

        if h > h2 and b[ny+dy][nx+dx] == h and visited[ny+dy][nx+dx] == 0:
            visited[ny+dy][nx+dx] = 1
            append((nx+dx, ny+dy, b[ny+dy][nx+dx]))

print("NO")