```cpp
#include<bits/stdc++.h>
using namespace std;
long long s,V,t=470,h,m;
double a;
bool f=true;
int main(){
cin>>s>>V;
a=s/V;
while(a>1){
a--;
}
if(a==0)f=false;
t-=s/V;
if(f){
t--;
}
if(t>0){
h=t/60;
m=t%60;
}
else{
int a=0-t;
h=24-(a/60);
m=60-(a%60);
}
if(h<10)cout<<0;
cout<<h;
cout<<":";
if(m<10)cout<<0;
cout<<m;
return 0;
}
```
by unstopable @ 2022-07-19 21:40:43
# 70分
```cpp
#include<bits/stdc++.h>
using namespace std;
long long s,V,t=470,h,m;
double a;
bool f=true;
int main(){
cin>>s>>V;
a=s/V;
while(a>1){
a--;
}
if(a==0)f=false;
t-=s/V;
if(f){
t--;
}
if(t>0){
h=t/60;
m=t%60;
}
else{
int a=0-t;
h=24-(a/60);
m=60-(a%60);
}
if(h<10)cout<<0;
cout<<h;
cout<<":";
if(m<10)cout<<0;
cout<<m;
return 0;
}
```
by unstopable @ 2022-07-19 21:42:28
谢谢
by xuqinyang @ 2022-07-20 21:00:23