import java.io.*;
import java.util.*;

public class average {
  public static void main(String[] args) { try {
    int i; double current=0.0, sum;
    
    LineNumberReader Quelle = new LineNumberReader(new FileReader("average.in"));
    
    StringTokenizer Tokens = new StringTokenizer(Quelle.readLine());
    
    int sections = Integer.parseInt(Tokens.nextToken());

    double Length = Double.parseDouble(Tokens.nextToken());
    
    while(true) {
      sum=0.0;
      String Zeile = Quelle.readLine();
      if (Zeile==null) return;
      
      Tokens = new StringTokenizer(Zeile);
      String TeamString = Tokens.nextToken();
      
      for (i=0; i<(3-TeamString.length()); i++) {
      	System.out.print(' ');
      }
      System.out.print(TeamString);
      System.out.print(": ");
      
      for (i=0; i<sections; i++) {
      	current = parseTime(Tokens.nextToken());
	if (Double.isNaN(current)) {
	  break;
	}
	sum += current;
      }
      
      if (Double.isNaN(current)) {
      	System.out.println('-');
      } else {
      	print(sum/Length);
	
	System.out.println(" min/km");
      }      
    }   
  } catch (Exception E) {System.out.println(E);}}
  
  public static void print(double zahl) {
    int sum = (int)Math.round(zahl);
    int minutes = sum/60;
    int seconds = sum - (60*minutes);
    
    System.out.print(minutes);
    System.out.print(':');
    if (seconds<10) System.out.print('0');
    System.out.print(seconds);     
  }
  
  public static double parseTime(String time) {
    double result;
    
    if (time.charAt(0) == '-') return Double.NaN;
    
    result = time.charAt(0) - '0';
    result = (result * 6) + time.charAt(2) - '0';
    result = (result * 10) + time.charAt(3) - '0';
    result = (result * 6) + time.charAt(5) - '0';
    result = (result * 10) + time.charAt(6) - '0';
    return result;
  }  
}