#include <stdio.h>
#include <stdlib.h>
#include <math.h>

float fround(float c){
  if(c - floor(c) < 0.5)
    return floor(c);
  else
    return ceil(c);
}

int main(){
  FILE *input;
  float dist,f_sec;
  int n,i,j,k,team,hour,min,sec,s_hour,s_min,s_sec,a_min,a_sec,fail;
  char str[1024];

  input = fopen("average.in","r");

  memset(str,0,1024);
  fgets(str,1024,input);
  sscanf(str,"%d %f",&n,&dist);

  memset(str,0,1024);
  while(fgets(str,1024,input) != NULL){
    j = 3;
    str[j] = 0;
    team = atoi(str);
    s_hour = s_min = s_sec = a_sec = a_min = fail = 0;
    for(i = 0;i < n;i++){
      k = j + 1;
      j = j + 8;
      str[j] = 0;
      if(str[k] == '-')
	fail = 1;
      sscanf(&str[k],"%d:%d:%d",&hour,&min,&sec);
      s_hour = s_hour + hour;
      s_min = s_min + min;
      s_sec = s_sec + sec;
    }
    if(fail == 0){
      f_sec = (s_sec + 60*s_min + 3600*s_hour) / dist;
      a_sec = fround(f_sec);
      a_min = a_sec / 60;
      a_sec = a_sec % 60;
      printf("%3d: %d:%02d min/km\n",team,a_min,a_sec);
    }
    else
      printf("%3d: -\n",team);
  }

  fclose(input);
  return 0;
}