There are 4 balls of red, yellow, blue, and green in the pocket, and there are 4 balls of each color. Xiaohua closes his eyes and touches the balls from the pocket, so how many balls must he touch at least? , in order to ensure that there are balls of each color in the drawn balls?
口袋里装有红、黄、蓝、绿这4种颜色的球，且每种颜色的球都有4个，小华闭着眼睛从口袋里往外摸球，那么他至少要摸出多少个球，才能保证摸出的球中每种颜色的球都有？
<gadget id="calculator">4 + 4 + 4 + 1</gadget>
<output>13</output>

<result>13</result>