#include<iostream>
using namespace std;
int main() 
{
	int s, v, t, tt;
	cin >> s >> v;
	t = s / v + 11;
	tt = 8 * 60 - t;
	if (tt > 0) 
		printf("%02d:%02d", tt / 60, tt % 60);
	if (tt == 0) {
		cout << "00" << ":" << "00";
	}
	if (tt < 0&&tt>=-960)
		printf("%02d:%02d", 23 + (tt / 60), 60 + tt % 60);
	return 0;
}