Members of a certain squadron have subscribed to three magazines A, B, and C. It is known that each person can subscribe to at most 3 magazines and at least 1 magazine. How many ways are there in total to subscribe to magazines?
某中队队员共订阅了A、B、C三种杂志，已知每人最多订阅3种，最少订阅1种，共有多少种订阅杂志的方法．
<gadget id="calculator">3 + 3 + 1</gadget>
<output>7</output>

<result>7</result>