#include <stdio.h>
#include <math.h>
int main()
{
double s,v;int t,h,m;
scanf("%lf%lf",&s,&v);
t=ceil(s/v);
h=(1440-t-10)/60;
m=(1440-t-10)%60;
if(h<=16&&m>=10)
printf("%d:%d",8+h,m);
if(h>16&&m<10)
printf("0%d:0%d",h-16,m);
if(h<=16&&m<10)
printf("%d:0%d",8+h,m);
if(h>16&&m>=10)
printf("0%d:%d",h-16,m);
return 0;
}
