#include<bits/stdc++.h>
using namespace std;
int main()
{
    int s,v,fz;
    cin>>s>>v;
    if(s%v==0)
    {
    	fz=s/v;
	}
    else
    {
    	fz=s/v+1;
	}
	int xs=0;//小时 
	while(fz>60)
	{
		if(fz>=60)
		{
			fz=fz-60;
			xs++;
		}
	}
	int sxs,sfz;//sxs总小时，sfz总分钟 
	if(xs>8)
	{
		sxs=xs-8;
		sxs=24-sxs-1;
		sfz=60-fz-10;
	}
	else
	{
		sxs=8-1-xs;
		sfz=60-10-fz;
	}
	if(sfz<10&&sxs<10)
	{
		cout<<"0"<<sxs<<":"<<"0"<<sfz;
	}
	else if(sfz<10&&sxs>10)
	{
		cout<<sxs<<":"<<"0"<<sfz;
	}
	else if(sfz>10&&sxs<10)
	{
		cout<<"0"<<sxs<<":"<<sfz;
	}
	else
	{
		cout<<sxs<<":"<<sfz;
	}

}