#include<iostream>
using namespace std;
#include<cstdio>
#include<cmath>
int main()
{
	double s, v, t;
	int h = 7, min = 0;
	cin >> s >> v;
	t = ceil(s / v) + 10;
	while (t >= 60)
	{
		t -= 60;
		h--;
		if (h == 0)
			h = 24;
	}
	min = t;
	min = 60 - t;
	if (min == 60)
	{
		min = 0;
		h++;
		if (h == 24)
			h = 0;
	}
	printf("%02d:%02d", h, min);
		return 0;
}