2336: Deadline

     There are N bugs to be repaired and some engineers whose abilities are roughly equal. And an engineer can repair a bug per day. Each bug has a deadline A[i].

      Question: How many engineers can repair all bugs before those deadlines at least?

      1<=n<= 1e6. 1<=a[i] <=1e9 

       There are multiply test cases.

       In each case, the first line is an integer N , indicates the number of bugs. The next line is n integers indicates the deadlines of those bugs. 

       There are one number indicates the answer to the question in a line for each case. 

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