#include<stdio.h>
#include <math.h>
double s;
double v;
int t;
int main()
{
	scanf("%lf%lf",&s,&v);
	t = ceil(s/v)+10;	
	int hour= t/60;	
	int minute =ceil(t%60);
	
	hour = 7-hour;
	minute = 60 - minute;
	if(hour<0)
	{hour=hour+24;
	}
	else if(hour<10)
	{
	   printf("0%d:",hour);
	}
	else
	{
		printf("%d:",hour);
	}
	
	if(minute<10)
	{
		printf("0%d",minute);
	}
	 else
	 {
	 	printf("%d",minute);
	 }
	 
	return 0;
}