代码：

#include<bits/stdc++.h>
using namespace std;
int main()
{
    
    int timeh=7,timemin=50,s,v,times=0,timesy=0;;
    cin>>s>>v;
    timesy=s%v;
    times=(s-timesy)/v+1;
    while(times>=60){
        times-=60;
        timeh-1;
    }
    if(times>0){
        if(times>50){
            timeh-=1;
            times=60-times;
            timemin+=times;
        }
        else
        {
            timemin-=times;
        }
    }
    cout<<"0"<<timeh<<":"<<timemin;
    return 0;
}