```cpp
#include<bits/stdc++.h>
using namespace std;
int s,v,t;
int main(){
cin>>s>>v;
t=s/v+(s%v!=0);
t=7*60+50+24*60-t;
if(t/60>=24)
t-=24*60;
if(t/60<10)
cout<<0;
cout<<t/60<<":";
if(t%60<10)
cout<<0;
cout<<t%60;
return 0;
}
```
by HarryMalfoy @ 2023-12-31 10:56:24