#include <stdio.h>
#include <math.h>
int main ()
{
	int n=8*60;
	int t;
	double s,v;
	scanf("%lf%lf",&s,&v);
	if(s>=1&&v<=10000){
		t=ceil(s/v);
		int a,b;
		if(t<(8*60)){
			a=t%60;
			b=t/60;
			printf("%02d:%02d",8-b-1,60-a-10);
		}else if(t>(8*60)&&t<(8*60+24*60)){
			t-=n;
			a=t%60;
			b=t/60;
			printf("%02d:%02d",24-b-1,60-a-10);
		}
	}
	return 0;
}