#include<stdio.h>
int main()
{
	int s, v, t, hour, min; char c = '0'; char d='0';
	scanf("%d %d",&s, &v);
	t = (s/v)+1;
	hour = t / 60; min = t % 60;
	hour = 7 - hour; min = 60 - min;
		if (min <= 0) { hour -= 1; min = 60 + min; }
		while (hour <= 0){
			if (hour <= 0) { hour = 24 + hour; }
		}
		min -= 10;
		if (hour > 9) c = NULL;
		if (min>9) d= NULL;
	printf("%c%d:%c%d",c,hour,d, min);
	return 0;
}```