#include<stdio.h>
int main()
{
	int a,b,c;
	scanf("%d%d",&a,&b);
	if(a%b==0) c=a/b;
	else c=a/b+1;
	c+=10;
	c=c%1440;
	if(c>480) c=480+24*60-c;
	else c=480-c;
	int d,e;
	d=c/60;
	e=c%60;
	if(d<10) printf("0");
	printf("%d:%d",d,e);
	if(e==0) printf("0");
	return 0; 
 }