#include<iostream>
using namespace std;
int main() {
	int s, v;
	cin >> s >> v;
	int t = s / v;
	if (s % v != 0) t++;
	int sum = t + 10;
	int hour = sum / 60;
	int minute = sum - hour * 60;
	if (hour < 8)
		cout << 0 << 7 - hour << ":" << 60 - minute;
	if (hour >= 8)
		cout << 24 + 7 - hour << ":" << 60 - minute;
	return 0;
}