from collections import deque

H, W = map(int, input().split())
sy, sx, gy, gx = map(lambda x: int(x) - 1, input().split())

S = [list(map(int, input())) for _ in range(H)]

visited = [[False] * W for _ in range(H)]
visited[sy][sx] = True

direction = [(-1, 0), (0, 1), (1, 0), (0, -1)]

que = deque([(sy, sx)])

while que:
    y, x = que.popleft()

    for dy, dx in direction:
        ny, nx = y + dy, x + dx
        nny, nnx = ny + dy, nx + dx
        if not (0 <= ny < H and 0 <= nx < W):
            continue
        if visited[ny][nx]:
            continue
        if abs(S[ny][nx] - S[y][x]) <= 1:
            visited[ny][nx] = True
            que.append((ny, nx))

        if not (0 <= nny < H and 0 <= nnx < W):
            continue
        if visited[nny][nnx]:
            continue
        if S[nny][nnx] == S[y][x] and S[nny][nnx] > S[ny][nx]:
            visited[nny][nnx] = True
            que.append((nny, nnx))

print("YES" if visited[gy][gx] else "NO")