#include<iostream>;
using namespace std;
int main() {
	double s, v;
	cin >> s >> v;
	double t1 = s / v;
	int t2 = s / v;
	int t = 0;
	if (t1 == t2) {
		t = t1;
}
	else {
		t = t2 + 1;
	}
	t = t + 10;
	if ((t / 60) <8) {
		if (t % 60 == 0) {
			cout << "0" << 8 - t / 60 << ":" << "00" << endl;
		}
		else if(t/60==0){
			cout << "0" << 8 - (t / 60)-1 << ":" << 60 - (t - (t / 60) * 60) << endl;
		}
		else {
			cout << "0" << 8 - (t / 60) - 1 << ":" << 60 - (t - (t / 60) * 60) << endl;
		}
	}
	else if (double(t) / 60.0 == 8) {
		cout << "00" << ":" << "00" << endl;
	}
	else {
		if (t % 60 == 0) {
			cout << 24 - (t/60 - 8) << ":" << "00" << endl;
		}
		else {
			cout << 24 - (t / 60 - 8) - 1 << ":" << 60 - (t - t / 60 * 60) << endl;
		}
	}
}