#include <bits/stdc++.h>
using namespace std;

int main() {
	int s, v;
	int h, a, b, c, d;
	cin >> s >> v;
	a = s / v;
	if (s / v != 0) {
		a = a + 1;
	} else {
		a = a + 0;
	}
	a = a + 10;
	b = 8 * 60;
	h = b - a;
	if (h < 0) {
		h = h + 24 * 60;
	}
	c = h / 60;
	d = h % 60;

	if (c < 10 && d < 10) {
		printf("0%d:0%d", c, d);
	} else if (d < 10) {
		printf("%d:0%d", c, d);
	} else if (c < 10) {
		printf("0%d:%d", c, d);
	} else {
		printf("%d:%d", c, d);
	}
	return 0;

}