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

f = [[True] * w for _ in range(h)]

t = [[sy - 1, sx - 1]]
f[sy - 1][sx - 1] = False

while len(t) > 0:
    s = []
    for y, x in t:
        if x > 0:
            if f[y][x - 1]:
                f[y][x - 1] = False
                s.append([y, x - 1])
        if y > 0:
            if f[y - 1][x]:
                f[y - 1][x] = False
                s.append([y - 1, x])
        if x < w - 1:
            if f[y][x + 1]:
                f[y][x + 1] = False
                s.appen([y, x + 1])
        if y < h - 1:
            if f[y + 1][x]:
                f[y + 1][x] = False
                s.append([y + 1, x])
    t = s
    if f[gy - 1][gx - 1] == False:
        break

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