#include<bits/stdc++.h>
using namespace std;
double s,v;
int time_all,hour,time_use,minute;
int main()
{
	cin>>s>>v;
	time_all=8*60+24*60;
	time_use=ceil(s/v)+10;
	time_all-=time_use;
	if(time_all>=24*60) time_all-=24*60;
	hour=time_all%60;
	minute=time_use/60;
	if(hour<10)
	{
		if(minute<10) cout<<"0"<<hour<<":0"<<minute;
		else cout<<"0"<<hour<<":"<<minute;
	}
	else
	{
		if(minute<10) cout<<hour<<":0"<<minute;
		else cout<<hour<<":"<<minute;
	}
	return 0;
}