#include<stdio.h>
#include<math.h>
int main()
{
int s,v,t,a,b;
scanf("%d %d",&s,&v);
t=ceil(1.0*s/v);
a=(8*60-10-t)/60;
b=(8*60-10-t)%60;
printf("%02d:%02d",a,b);
return 0;
}