#include<bits/stdc++.h>
using namespace std;
int s,v;
int pd(int k)
{
	if(k<=8)	return 8-k;
	if(k>8)	return 32-k;
		
}
int main()
{
//	freopen(".in","r",stdin);
//	freopen(".out","w",stdout);
	cin>>s>>v;
	int w=s/v+10;
	if(s%v>0)	w++;
	int h=w/60;
	int m=w%60;
	if(m==0)
	{
		if(pd(h)/10<1)	cout<<"0"<<pd(h)<<":"<<"00";
		else	cout<<pd(h)<<":"<<"00";
	}
	if(m>0)
	{
		if((pd(h)-1)/10<1)	cout<<"0"<<pd(h)-1<<":"<<60-m;
		else	cout<<pd(h)-1<<":"<<60-m;
	}
//	fclose(stdin);
//	fclose(stdout);
}