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), (-2, 0), (0, 2), (2, 0), (0, -2)]

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

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

    for dy, dx in direction:
        ny, nx = y + dy, x + dx
        if 0 <= ny < H and 0 <= nx < W:
            if visited[ny][nx]:
                continue
            flg = False
            if abs(dy + dx) == 2:
                if S[ny][nx] == S[y][x]:
                    flg = True
            else:
                if abs(S[ny][nx] - S[y][x]) <= 1:
                    flg = True
            if flg:
                visited[ny][nx] = True
                que.append((ny, nx))


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