#include<iostream>
#include<cstdio>
using namespace std;
int main() {
	double s, v;
	cin >> s >> v;
	int t = ceil(s / v);
	int sum = t + 10;
	int sum_minute = 8 * 60 - sum;
	int hour = sum_minute / 60;
	int minute = sum_minute % 60;
	printf("%02d:%d", hour, minute);
	
}