#include<bits/stdc++.h>
using namespace std;
int s,v,ans,ans1,ans2;
int main(){
	cin>>s>>v;
	ans+=s/v;
	if(s%v!=0)ans++;
	ans+=10;
	ans1=ans/60;
	ans2=ans%60;
	if(ans2==0){
		if(ans1<=8)
			cout<<0<<8-ans1<<":00"<<endl;
		else{
			if(ans1<=22)
				cout<<32-ans1<<":00"<<endl;
			else
				cout<<0<<32-ans1<<":00"<<endl;
		}
		return 0;	
	}
	if(ans1<=7){
        if(ans2>50){
            cout<<0<<8-ans1-1<<":"<<0<<60-ans<<endl;
        }    
        else cout<<0<<8-ans1-1<<":"<<60-ans2<<endl;
    }
	else{
		if(ans1<=22){
            if(ans2>50){
                cout<<31-ans1<<":"<<0<<60-ans2<<endl;  
            }
            else cout<<31-ans1<<":"<<60-ans2<<endl;
        }
		else {
            if(ans2>50)
                cout<<"0"<<31-ans1<<":"<<0<<60-ans2<<endl;
            else cout<<"0"<<31-ans1<<":"<<60-ans2<<endl;
        }
    }
	return 0; 
}