#include<iostream>
using namespace std;
int main()
{
	int h1,h2,h3,h4,p;
	double s,v,o;                   
	cin>>s>>v;
	o=s/v;
	p=int(o);
	if (o>p){o=o+1;}
	else{o=p;}
	h1=o+10;
	if (h1<=480 or h1>1320)
	{
		if (h1<=480)
		{h2=480-h1;}
		else 
		{h2=1920-h1;}
		h3=h2/60;
		h4=h2%60;
		cout<<"0"<<h3<<":"<<h4;
	}
	else
	{
		h2=1920-h1;
		h3=h2/60;
		h4=h2%60;
		cout<<h3<<":"<<h4;
	}
	return 0;
}