```c
#include <bits/stdc++.h>
using namespace std;
double s,v,m;
int n,a,t,b;
int main(){
cin>>s>>v;
n = 8 * 60 + 24 * 60;
t = ceil(s / v) + 10;
n = n - t;
if(n >= 24 * 60){
n -= 24 * 60;
}
b = n % 60;
a = n / 60;
if(a < 10){
if(b < 10){
cout<<"0"<<a<<":0"<<b;
}
else{
cout<<"0"<<a<<":"<<b;
}
}
else{
if(b < 10){
cout<<a<<":0"<<b;
}
else{
cout<<a<<":"<<b;
}
}
return 0;
}
```
@[wxyjw](/user/800366)
by Li_mz__ @ 2022-11-02 19:30:51