#include <iostream>
using namespace std;
int main()
{
	int s,u,mintime,foutime;
	float min;
	cin >> s >> u;
	min = s / (float)u + 10;
	foutime = (8 * 60 - (int(min) / 60 + int(min))) / 60;
	mintime = (8 * 60 - (int(min) / 60 + int(min))) % 60 - 1;
	cout << foutime << ':' << mintime;
	return 0;
}