#include <iostream>
#include<iomanip>
#include<cmath>
using namespace std;

int main()
{
	int s = 0; int v = 0;
	cin >> s >> v;
	double time = (double)s / (double)v;
	if (time > 1440)
		time = 1440.0;
	int hh = time / 60;
	double mm = time - hh * 60;
	int HH = (7 + 24-hh) % 24;
	int MM = 60 - 10 - (int)(ceil(mm));
	cout <<setw(2)<<setfill('0') << HH << ":" <<setw(2)<< MM;
	return 0;

}