# 入力 
h, w = map(int, input().split())
sx, sy, gx, gy = map(lambda x: x - 1, map(int, input().split()))
# sx, sy, gx, gy = sx - 1, sy - 1, gx - 1, gy - 1

b = [[] for i in range(h)]

for i in range(h):
    line = input()

    for takasa in line:
        b[i].append(int(takasa))

# print(b)

dx = [1, 0, -1, 0, 2, 0, -2, 0,]
dy = [0, 1, 0 ,-1, 0, 2, 0, -2,]

ikeru = [[None] * w for i in range(h)]

# print(ikeru)

ikeru[sx][sy] = True
tugis = [(sx, sy)]
tansaku_zumi = set()

# print(tugis[0][0])

while tugis:
    cur = tugis.pop()

    for i in range(len(dx)):
        if 0 <= cur[0] + dx[i] < h and 0 <= cur[1] + dy[i] < w:
            if i > 3 and b[cur[0]][cur[1]] == b[cur[0] + dx[i]][cur[1] + dy[i]]:
                if b[cur[0]][cur[1]] > b[cur[0] + dx[i - 4]][cur[1] + dy[i - 4]]:
                    if (cur[0] + dx[i], cur[1] + dy[i]) not in tansaku_zumi:
                        ikeru[cur[0] + dx[i]][cur[1] + dy[i]] = True
                        tugis.append((cur[0] + dx[i], cur[1] + dy[i]))
            elif i <= 3 and abs(b[cur[0] + dx[i]][cur[1] + dy[i]] - b[cur[0]][cur[1]]) <= 1:
                if (cur[0] + dx[i], cur[1] + dy[i]) not in tansaku_zumi:
                    ikeru[cur[0] + dx[i]][cur[1] + dy[i]] = True
                    tugis.append((cur[0] + dx[i], cur[1] + dy[i]))

    tansaku_zumi.add(cur)

# print(sorted(list(tansaku_zumi)))

if (gx, gy) in tansaku_zumi:
    print('YES')
else:
    print('NO')