14. As shown in Figure 4, $ABCD - A^{\prime} B^{\prime} C^{\prime} D^{\prime}$ is a rectangular prism, $A^{\prime} = 50 \mathrm{~cm}, AB$
$$
=40 \mathrm{~cm}, AD=30 \mathrm{~cm} \text {, }
$$

The top and bottom faces are each divided into
$3 \times 4$ small squares,
each with a side length of $10 \mathrm{~cm}$, resulting in
points $E, F, G, H$ and $E^{\prime}$,
$F^{\prime}, G^{\prime}, H^{\prime}$. Assuming an ant crawls at a speed of $2 \mathrm{~cm}$ per second, the minimum time it takes for the ant to crawl from point $E$ on the bottom face to point $G^{\prime}$ on the top face along the surface is $\qquad$ seconds.
$14.10 \sqrt{17}$