70分，8/9/10三个点出错，求助呜呜呜呜呜······

帮我改亿下：

#include<bits/stdc++.h>
using namespace std;
int main(){
	int s,v,hour = 0,min = 470;
	float time = 0;
	cin >> s >> v;
	time = s / v;
	if (time > int(time)){
		min -= (int(time) + 1);
	}else{
		min -= (int(time) + 1);
	}
	hour = min / 60;
	min %= 60;
	cout << 0 << hour << ":";
	if (min < 10){
		cout << 0 << min;
	}else{
		cout << min;
	}
}