If 10 identical apples are distributed to A, B, and C, and it is allowed that some people cannot be assigned, how many ways are there in total?
10个相同的苹果分给甲，乙，丙3个人，允许有人分不到，则共有多少种分法．
<gadget id="calculator">10 + 3</gadget>
<output>13</output>

<gadget id="calculator">13 - 1</gadget>
<output>12</output>

<gadget id="calculator">12 * 11</gadget>
<output>132</output>

<gadget id="calculator">2 * 1</gadget>
<output>2</output>

<gadget id="calculator">132 / 2</gadget>
<output>66</output>

<result>66</result>