An opaque box contains 3 red glass balls, 4 black glass balls, and 5 white glass balls. To ensure that the glass balls taken out have all three colors, how many should he take out at least?
一个不透明的盒子里装了红玻璃球3个、黑玻璃球4个、白玻璃球5个，要保证取出的玻璃球三种颜色都有，他应保证至少取出多少个？
<gadget id="calculator">4 + 5 + 1</gadget>
<output>10</output>

<result>10</result>