#include```cpp

- 
#include<cmath>
using namespace std;
int main()
{
	double s, v;
	int a, b, c,d;
	cin >> s >> v;
	double t;
	t = ceil(s / v) + 10;
	a = 8 * 60+24*60;
	b = a - t;
	if (b >= 24 * 60) b -= 24 * 60;
	c = b % 60;
	d = b / 60;
	if (d > 10) {
		if (c > 10) { cout << d << ":" << c;}
		else { cout << d << ":0" << c; }
	}
	else {
		if (c > 10) { cout << "0"<<d << ":" << c; }
		else { cout << "0" <<d<< ":0" << c; }
	}


}