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

int main()
{
	int s,v,time_1,time,hour,minute;
	scanf("%d %d",&s,&v);
	time_1 = ceil(s * 1.0 / v);
	time = time_1 + 10;
	hour = (8 - (int)ceil(time * 1.0 / 60) + 24) % 24;
	minute = (60 - (time - (time / 60) * 60)) % 60;
	if(hour >= 0 && hour <= 9){
		if(minute == 0){
			printf("0%d:0%d",hour,minute);	
		}else{
			printf("0%d:%d",hour,minute);
		}		
	}else{
		if(minute == 0){
			printf("%d:0%d",hour,minute);
		}else{
			printf("%d:%d",hour,minute);
		}	
	}
	return 0;
}