#include<stdio.h>
int main()
{
   int s;
   int v;
   int t;
   int hour;
   int minute;
   
   scanf("%d%d",&s,&v);
   
   if(s%v==0)
   {
   	t=s/v+10;
   }
   else
   {
   	t=s/v+11;
   }
   hour=t/60;
   minute=t%60;
   if(t<480)
   {
   	hour=7-hour;
   	minute=60-minute;
   }
   if(t>=480)
   {
   	hour=23-hour;
   	minute=60-minute;
   }
   printf("%02d:%02d",hour,minute);
   
	return 0;
}