#include<iostream>
using namespace std;
int main() {
	int s, v, m, h;
	cin >> s >> v;
	if (s%v == 0) {
		if (s / v <= 470) {
			m = (480 - s / v - 10) % 60;
			h = (480 - s / v - 10) / 60;
		}
		else { m = (1440 - s / v - 10) % 60;h = (1440 - s / v - 10) / 60; }
	}
	else {
		if (s / v <= 470)
		 {
			m = (480 - s / v - 10 - 1) % 60;
			h = (480 - s / v - 10-1) / 60;
		}
		else { m = (1440 - s / v - 10-1) % 60;h = (1440 - s / v - 10 - 1) / 60; }
	}
	if (m < 10) {
		if (h < 10) { cout << "0" << h << ":" << "0" << m << endl; }
		else { cout << h << ":" << "0" << m << endl; }
	}
	if (m >= 10) {
		if (h < 10) { cout << "0" << h << ":" << m << endl; }
		else { cout << h << ":" << m << endl; }
	}




	return 0;}