#include<iostream>
#include<cmath>
using namespace std;
int main()
{
	int s, v, t1, t2, h, m;
	cin >> s >> v;
	if(s%v==0)
	{
		t1 = 10 + s/v;
	}
	else
	{
		t1 = 11 + s/v;
	}
	t2 = 480 - t1;
	h = t2 / 60;
	m = abs(t2) - abs(h) * 60;
	if(h < 0)
	{
		h = 24 + h;
	}
	if(h<10)
	{
		if(m<10)
		{
			cout << 0 << h << ":" << 0 << m;
			return 0;			
		}
		else
		{
			cout << 0 << h << ":" << m;
			return 0;
		}
	}
	else
	{
		if(m<10)
		{
			cout << h << ":" << 0 << m;
			return 0;
		}
		else
		{
			cout << h << ":" << m;
			return 0;
		}
	}