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

int main()
{
	int s,v;
	cin >> s >> v;
	if(s % v == 0)int T = s / v + 9;
	else T = s / v + 10;
	int H= T / 60;
	int M = T - 60 * H;
	int h;
	int m;
	h = 8 - H - 1;
	m = ceil(60 - M - 1);
	
	if(h < 0)h += 24;
	if(h <= 9 && m <= 9)cout <<"0"<< h << ":"<<"0" <<m;
	if(h <= 9 && m > 9)cout <<"0"<< h << ":"<<m;
	if(h > 9 && m <= 9)cout << h << ":"<<"0"<<m;
	if(h > 9 && m > 9)cout << h << ":"<<m;
	return 0;
 }