Question: In a file you have the number of questions solved by students from different groups. Write a program that calculates the average of all groups and sorts them in descending according to the averages. If there are two groups with the same average show them in ascending order according to the group names.

Input specification: At the beginning, you will be given two integers: the number of students (n) and the number of top m groups to list. Then in the following n lines, you will be given two information: the group of the student (grp) and the number of questions solved (k) by this student, where

• grp is a string with at most 10 chars
• k is a positive integer not greater than 10,000

Output specification: Show top m groups.

Explanation: The average of

• CEN1 is 24,
• ECE1 is 20, and
• CEN2 is 10.