#include <bits/stdc++.h>
using namespace std;
int main()
{
	int s,v,min,hour,minute;
	cin>>s>>v;
	if(s%v==0) min=s/v+10;
	else min=s/v+1+10;
	hour=min/60;
	minute=min%60;
	int sthour=8,stminute=0;
	if(stminute-minute<0)
	{
		stminute+=60;
		sthour-=1;
	}
	if(sthour-hour<0)
		sthour+=24;
	if(sthour-hour>0&&sthour-hour<=9){
		if(stminute-minute>=0&&stminute-minute<=9)
	cout<<0<<sthour-hour<<':'<<0<<stminute-minute;
		else cout<<0<<sthour-hour<<':'<<stminute-minute;
	}
	else {
		if(stminute-minute>=0&&stminute-minute<=9)
		cout<<sthour-hour<<':'<<0<<stminute-minute;
		else
			cout<<sthour-hour<<':'<<stminute-minute;
	}
return 0;
}