#include <stdio.h>
#include <math.h>

int main(){
	double s,v;
	scanf("%lf %lf",&s,&v);
	double mind;
	mind=s/v+10;
	//printf("%.15f\n",mind);
	int min;
	min=ceil(mind);
	int h=0;
	h=min/60;
	min=min%60;
	if(h<=7){
		h=7-h;
		min=60-min;
		printf("%02d:%2d",h,min);
	}
	if(h>=8){
		h=31-h;
		min=60-min;
		printf("%02d:%2d",h,min);
	}
	return 0;
}