How many different ways are there to choose 4 shoes from 5 pairs of different sizes, at least 2 of which are matched into a pair?
从5双不同尺码的鞋子中任取4只，其中至少有2只配成一双，共有多少种不同的取法．
<gadget id="calculator">210 - 80</gadget>
<output>130</output>

<result>130</result>