8，9，10测试点错了

#include<iostream>
using namespace std;
int main()
{
	int s,v,t, hour,min;
	cin >> s >> v;
	t = s % v == 0 ? s / v+10 : s / v + 11;
	if (t > 480)
	{
		hour = 24-(16 * 60 - t) / 60;
		min = (16 * 60 - t) % 60;
	}
	else
	{
		hour = (480 - t) / 60;
		min = (480 - t) % 60;
	}
	if (hour < 10 && min >= 10)
		cout << 0 << hour << ":" << min;
	else if (min < 10 && hour >= 10)
		cout << hour << ":" << 0 << min;
	else if (min < 10 && hour < 10)
		cout << 0 << hour << ":" << 0 << min;
	else
		cout << hour << ":" << min;
	return 0;
}