#include <stdio.h>
int main()
{
	int s,v,t,a;
	scanf("%d%d",&s,&v);
	if(s%v==0)
	t=s/v;
	else t=s/v+1;
    a=t/60;
    if(a<=8)
	{
      if(t%60==0)
       printf("0%d:50",8-a);
       else
	   {
	     if(60-t%60-10>=0)	printf("0%d:%d",8-a-1,60-t%60-10);
	     else 	printf("0%d:%d",8-a-2,60-t%60-10+60);
	   }
    }
    else 
    {
      if(t%60==0)
       printf("%d:50",24-(a-8));
       else
	   {
	    if(60-t%60-10>=0)	printf("%d:%d",24-(a-8),60-t%60-10);
	    else printf("%d:%d",22-(a-8),60-t%60-10+60);
	   }		
	}
   	  return 0;
}