编程题：student score

Input a batch of student scores, calculate the average score, and count the number of failed students (score <60).

### Input Specification:

Enter a student score in each line, with a negative number as the sign of the end of the input.

### Output Specification:

Output the average score (keep 2 decimal places) and the number of failed students in the specified format. If tNo studentsre is no student data, output No students

### Sample Input #1:
in
90
78
56
34
55
68
-1


### Sample Output #1:
out
average=63.50 fail=3

### Sample Input #2:
in
-8


### Sample Output #1:
out
No students











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