from collections import deque

h, w = map(int, input().split())
sx, sy, gx, gy = map(int, input().split())
sx, sy, gx, gy = sx-1, sy-1, gx-1, gy-1
b = [list(input()) for _ in range(h)]

way = [(-1, 0), (1, 0), (0, -1), (0, 1)]
dist = [[float('inf')]*w for _ in range(h)]
dist[sx][sy] = 0
que = deque([(sx, sy)])
while que:
    x, y = que.popleft()
    hight = int(b[x][y])
    for i, j in way:
        nx = x + i
        ny = y + j
        if 0 <= nx < h and 0 <= ny < w:            
            nhight = int(b[nx][ny])
            if -1 <= hight - nhight <= 1 and dist[nx][ny] == float('inf'):
                dist[nx][ny] = dist[x][y] + 1
                que.append((nx, ny))
        nx += i
        ny += j
        if 0 <= nx < h and 0 <= ny < w:
            nhight = int(b[nx][ny])
            if hight == nhight and dist[nx][ny] == float('inf'):
                dist[nx][ny] = dist[x][y] + 1
                que.append((nx, ny))

if dist[gx][gy] != float('inf'):
    print('YES')
else:
    print('NO')