#include <iostream>
using namespace std;
int main()
{
	double s, v;
	cin >> s >> v;
	if (s >= 1 && v <= 1e4)
	{
		double time;
		int time2;
		time = s / v + 10;
		time2 = 8 * 60 - time;
		int HH, MM;
		HH = time2 / 60;
		MM = time2 % 60;
		printf("%02d:%02d", HH, MM);
	}
	system("pause");
	return 0;
}