#include<stdio.h>
#include<math.h>
int a[24]={8,7,6,5,4,3,2,1,24,23,22,21,20,19,18,17,16,15,14,13,12,11,10,9};
int main()
{
	int s,v,h,m,c,d;
	scanf("%d %d",&s,&v);
	d=((s/v)+1);
	c=(d+10)/60;
	m=50-d+60*c;
	if(m==60)
	{
		printf("%02d:%02d",a[c],60*c-d-10);
	}
	else
	{
		printf("%02d:%02d",a[c+1],50-d+60*c);
	}
	
	return 0;
}