70分代码如下，希望高手来指点下！

#include<bits/stdc++.h>
using namespace std;
int s,v,k=10;
int main()
{
	cin>>s>>v;
	if(s%v==0)
		k+=s/v;
	else
		k+=s/v+1;
	cout<<"0"<<8-k/60-1<<":";
	k%=60;
	if(60-k<10)
		cout<<"0";
	cout<<60-k;
    return 0;
}