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