#include<iostream>
using namespace std;
int main()
{
	int s,v,h,m,t;
	cin>>s>>v;
	if((double)s/v==0)
		t=s/v;
	else
		t=s/v+1;
	h=(24*60+480-t-10)/60;
	m=60-(t+10)%60;
	if(h>=24)
		h-=24;
	if(h/10==0&&m/10==0)
		cout<<'0'<<h<<':'<<'0'<<m<<endl;
	else if(h/10==0&&m/10!=0)
		cout<<'0'<<h<<':'<<m<<endl;
	else if(h/10!=0&&m/10==0)
		cout<<h<<':'<<'0'<<m<<endl;
	else
		cout<<h<<':'<<m<<endl;