#include <bits/stdc++.h>
using namespace std;
int main(){
    int s,v,t=10;
    cin>>s>>v;
    if(v==0) cout<<"07:50";
    else{
        if(s%v==0) t=t+s/v;
        else t=t+s/v+1;
        int ts,tf;
        ts=t/60;
        tf=t-60*ts;
        if(ts<8){
            if(tf>50){
                cout<<"0"<<7-ts<<":0"<<tf;
            }
            else{
                cout<<"0"<<7-ts<<":"<<60-tf;
            }
        }
        else if(ts>=8 and ts<=14){
            ts=ts-8;
            if(tf>50){
                cout<<23-ts<<":0"<<tf;
            }
            else{
                cout<<23-ts<<":"<<60-tf;
            }
        }
        else{
            ts=ts-14;
            if(tf>50){
                cout<<9-ts<<":0"<<tf;
            }
            else{
                cout<<9-ts<<":"<<60-tf;
            }
        }
    }
}

到底怎么才能搞才能让这段代码不是这么发啊烦死了整这么久都不会把它用代码块输出