from collections import deque

int1 = lambda x: int(x) - 1

H, W = map(int, input().split())
Sx, Sy, Gx, Gy = map(int1, input().split())
B = [[int(x) for x in input()] for _ in range(H)]

# bfs
d = deque([(Sx, Sy)])
visited = set(d)
while d:
    x, y = d.popleft()
    for dx, dy in ((0, 1), (1, 0), (0, -1), (-1, 0)):
        if 0 <= x + dx < H and 0 <= y + dy < W and (x + dx, y + dy) not in visited:
            if abs(B[x + dx][y + +dy] - B[x][y]) <= 1:
                d.append(((x + dx, y + dy)))
                visited.add((x + dx, y + dy))
    for dx, dy in ((0, 2), (2, 0), (0, -2), (-2, 0)):
        if 0 <= x + dx < H and 0 <= y + dy < W and (x + dx, y + dy) not in visited:
            if B[x + dx][y + +dy] == B[x][y]:
                d.append(((x + dx, y + dy)))
                visited.add((x + dx, y + dy))

print('YES' if (Gx, Gy) in visited else 'NO')