Average Student Grades

You are given data for a number of students, each with a list of their exam grades. Your task is to compute the average grade for each student, rounded to two decimal places. If a student does not have any grades, the average grade is 0.00.

The average is computed using the formula:

\( \text{average} = \frac{\text{sum of grades}}{\text{number of grades}} \)

You need to read the student data from standard input and output the results to standard output in the format:

student_name: average_grade

where average_grade is formatted to exactly two decimal places.

inputFormat

The input is read from standard input and has the following format:

1. The first line contains an integer N, denoting the number of students.
2. The following lines contain data for each student in blocks:
• The first line of each block contains the student's name (a string) followed by an integer M indicating the number of grades.
• If M is greater than 0, the next line contains M space-separated integers representing the student's grades.

For example:

4
Alice 3
90 85 88
Bob 3
70 80 75
Charlie 0
David 2
95 92

outputFormat

For each student (in the order they are given), output a single line in the following format:

student_name: average_grade

The average_grade must be rounded to two decimal places. For example:

Alice: 87.67
Bob: 75.00
Charlie: 0.00
David: 93.50

## sample

4
Alice 3
90 85 88
Bob 3
70 80 75
Charlie 0
David 2
95 92

Alice: 87.67
Bob: 75.00
Charlie: 0.00
David: 93.50

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