求大佬指错

#include<iostream>

using namespace std;
int main()
{
	int s,v,t,t1,t2,n=24;
	cin >> s >> v;
	if(s%v==0) t=s/v+10;
	else t=s/v+11;
	t1=t/60;
	t2=t%60;
	if(480-t>=0)
	{
		if(t2!=0)
		{	
			t1=7-t1;
			t2=60-t2;
			cout<<"0"<<t1<<":"<<t2;
		}
		else
		{
			t1=8-t1;
			cout<<"0"<<t1<<":"<<"00";
		}
	}
	else
	{
		if(t2!=0)
		{	
			t1=31-t1;
			t2=60-t2;
			cout<<t1<<":"<<t2;
		}
		else
		{
			t1=32-t1;
			cout<<t1<<":"<<"00";
		}
	}
}

将小时和分钟分开计的