#include<iostream>
using namespace std;
int main()
{
	int s,v,shijian,zong,hour,final;
	cin>>s>>v;
	if(s%v==0)
	{
		shijian=s/v;
	}
	else
	{
		shijian=s/v+1;
	}
	zong=shijian+10;
	if(zong<=60)
	{
		final=60-zong;
		cout<<07<<":"<<final;
	}
	if(60<zong<=480)
	{
		hour=8-zong/60-1;
		final=60-zong%60;
		cout<<0<<hour<<":"<<final;
	}
	if(zong>480)
	{
		hour=24-(zong-480)/60-1;
		final=60-(zong-480)%60;
		if(hour>=10)
		{
			cout<<hour<<":"<<final;
		}
		else(hour<10);
		{
			cout<<0<<hour<<":"<<final;
		}
	}
			
	return 0;
}