h, w = map(int,input().split())
sx, sy, gx, gy = map(int,input().split())
sx -= 1
sy -= 1
gx -= 1
gy -= 1
b = [list(input()) for j in range(h)]

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

visited = [[False] * w for j in range(h)]
visited[sx][sy] = True
qx = []
qy = []
qx.append(sx)
qy.append(sy)

while len(qx) != 0:
    curx = qx.pop(0)
    cury = qy.pop(0)
    cur = int(b[curx][cury])

    for i in range(4):
        nextx = curx + dx[i]
        nexty = cury + dy[i]
        if 0 <= nextx < h and 0 <= nexty < w:
            pass
        else:
            continue

        if abs(cur - int(b[nextx][nexty])) <= 1:
            if not visited[nextx][nexty]:
                visited[nextx][nexty] = True
                qx.append(nextx)
                qy.append(nexty)

    for i in range(4):
        nextx = curx + ddx[i]
        nexty = cury + ddy[i]
        if 0 <= nextx < h and 0 <= nexty < w:
            pass
        else:
            continue

        if cur != int(b[nextx][nexty]):
            continue

        valleyx = curx + dx[i]
        valleyy = cury + dy[i]
        if int(b[valleyx][valleyy]) < cur:
            if not visited[nextx][nexty]:
                visited[nextx][nexty] = True
                qx.append(nextx)
                qy.append(nexty)

if visited[gx][gy]:
    print("YES")
else:
    print("NO")