#include <stdio.h>
int main()
{
	int s,v,time,h,m;
	scanf("%d%d",&s,&v);
	time = s/v;
	if(s%v!=0)
	{
	time++;
	}
	time+=10;//����
	if(time<=480)
	{
	h = time/60;
	m = time%60;
	printf("0%d:%d",7-h,60-m);
	}
	else
	{
		time = time-480;
		h = (1440-time)/60;
		m = (1440-time)%60;
		if(h<10)
		{
			printf("0");
		}
		printf("%d:",h);
		if(m<10)
		{
			printf("0");
		}
		printf("%d",m);
	}
	
	return 0;
 }