Several unit cubes are put together to form a big cube, and part of the side of the big cube is painted red and then separated. It turns out that there are 45 unit cubes that have not been painted. How many sides of the big cube are painted?
若干个单位立方体拼成一个大立方体，在大立方体的一部分侧面涂上红色后再分开，结果发现共有45个单位立方体没有被涂色，那么大立方体被涂色的侧面有多少个．
<gadget id="calculator">5 * 5 * 5</gadget>
<output>125</output>

<result>125</result>