h, w = map(int, input().split())

sx, sy, gx, gy = map(int, input().split())

B = [[int(i) for i in input()] for i in range(h)]

visited = [[0] * w + [1, 1] for i in range(h)] + [[1] * (w + 2)] * 2

from collections import deque
que = deque([sx - 1, sy - 1])
visited[sx - 1][sy - 1] = 1

while que:
    q1, q2 = que.popleft(), que.popleft()
    h = B[q1][q2]
    
    if visited[q1 + 1][q2] == 0 and abs(B[q1 + 1][q2] - h) < 2:
        visited[q1 + 1][q2] = 1
        que.extend([q1 + 1, q2])
    if visited[q1 - 1][q2] == 0 and abs(B[q1 - 1][q2] - h) < 2:
        visited[q1 - 1][q2] = 1
        que.extend([q1 - 1, q2])
    if visited[q1][q2 + 1] == 0 and abs(B[q1][q2 + 1] - h) < 2:
        visited[q1][q2 + 1] = 1
        que.extend([q1, q2 + 1])
    if visited[q1][q2 - 1] == 0 and abs(B[q1][q2 - 1] - h) < 2:
        visited[q1][q2 - 1] = 1
        que.extend([q1, q2 - 1])
    if visited[q1 + 2][q2] == 0 and B[q1 + 2][q2] == h and B[q1 + 1][q2] < h:
        visited[q1 + 2][q2] = 1
        que.extend([q1 + 2, q2])
    if visited[q1 - 2][q2] == 0 and B[q1 - 2][q2] == h and B[q1 - 1][q2] < h:
        visited[q1 - 2][q2] = 1
        que.extend([q1 - 2, q2])
    if visited[q1][q2 + 2] == 0 and B[q1][q2 + 2] == h and B[q1][q2 + 1] < h:
        visited[q1][q2 + 2] = 1
        que.extend([q1, q2 + 2])
    if visited[q1][q2 - 2] == 0 and B[q1][q2 - 2] == h and B[q1][q2 - 1] < h:
        visited[q1][q2 - 2] = 1
        que.extend([q1, q2 - 2])

if visited[gx - 1][gy - 1]:
    print('YES')
else:
    print('NO')