import queue

dy = [0, -1, 0, 1]
dx = [1, 0, -1, 0]


def bfs(sy, sx, gy, gx, field):
    q = queue.Queue()
    q.put((sy, sx))

    used = [[False] * len(field[0]) for i in range(len(field))]
    used[sy][sx] = True

    while not q.empty():
        now_y, now_x = q.get(0)
        now_h = field[now_y][now_x]

        if (now_y, now_x) == (gx, gy):
            break

        for i in range(len(dy)):
            next_y, next_x = now_y + dy[i], now_x + dx[i]

            if 0 <= next_y < len(field) and 0 <= next_x < len(field[0]) and not used[next_y][next_x]:
                next_h = field[next_y][next_x]
                if abs(now_h - next_h) <= 1:
                    q.put((next_y, next_x))
                    used[next_y][next_x] = True

        for i in range(len(dy)):
            next_y, next_x = now_y + dy[i] * 2, now_x + dx[i] * 2
            m_y, m_x = now_y + dy[i], now_x + dx[i]

            if 0 <= next_y < len(field) and 0 <= next_x < len(field[0]) and not used[next_y][next_x]:
                next_h = field[next_y][next_x]
                m_h = field[m_y][m_x]
                if now_h == next_h and now_h >= m_h:
                    q.put((next_y, next_x))
                    used[next_y][next_x] = True

    return used[gy][gx]


def main():
    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
    field = []
    for _ in range(h):
        field.append(list(map(int, input())))

    print("YES" if bfs(sx, sy, gx, gy, field) else "NO")


if __name__ == '__main__':
    main()