#include <stdio.h>
#include <math.h>
int main(){
  FILE *f=fopen("average.in","r");
  int n,t,h,m,s,i;
  long int z;
  double d,zeit,min,sec;
  char dummy[10000];
  fscanf(f," %i %lf ",&n,&d);
  ;x:
  fscanf(f," ");
  while (!feof(f)){
    fscanf(f," %i ",&t);
    printf("%3i: ",t);
    z=0;
    for (i=0;i<n;i++){int d;
      if ((d=fscanf(f," %i : %i : %i ",&h,&m,&s))!=3){
        fgets(dummy,sizeof dummy,f);
	if (dummy[1]=='-') printf("-\n"); else exit(1);
	goto x;
      }
      z+=h*3600+m*60+s;
    }
    zeit=floor((double)z/d+0.5);
    if (zeit<0.0) exit(1);
    min=floor(zeit/60.0);
    sec=floor(zeit-floor(zeit/60.0)*60.0);
    if (sec==0.0) printf("%.0f:00 min/km\n",min);
    else{
      printf("%.0f:",min);
      if (sec>=10.0) printf("%2.0f min/km\n",sec);
      else printf("0%.0f min/km\n",sec);
    }
    fscanf(f," ");
  }
  fclose(f);
  return 0;
}