H, W = map(int, input().split())
sx, sy, gx, gy = map(int, input().split())
sx -= 1
sy -= 1
gx -= 1
gy -= 1
G = [tuple(map(int, list(input()))) for _ in range(H)]

DX = (-1, 0, 1, 0, -1, -1, 1, 1)
DY = (0, 1, 0, -1, -1, 1, -1, 1)
DX = DX[:4]
DY = DY[:4]

vis = [[0] * W for _ in range(H)]
vis[sx][sy] = 1
q = [(sx, sy)]
while q:
    x, y = q.pop()
    now = G[x][y]
    for dx, dy in zip(DX, DY):
        nx = x + dx
        ny = y + dy
        if 0 <= nx < H and 0 <= ny < W:
            if not vis[nx][ny]:
                nxt = G[nx][ny]
                if abs(nxt - now) <= 1:
                    vis[nx][ny] = 1
                    q.append((nx, ny))
        nnx = nx + dx
        nny = ny + dy
        if 0 <= nnx < H and 0 <= nny < W:
            if not vis[nnx][nny]:
                nxt = G[nx][ny]
                nxtnxt = G[nnx][nny]
                if now == nxtnxt and now > nxt:
                    vis[nnx][nny] = 1
                    q.append((nnx, nny))

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