#include<bits/stdc++.h>

using namespace std;

int main()

{

	int s,v,d,x,h,m;
  	cin>>s>>v;
	if(s%v==0）
	d=s/v;
	else
	d=s/v+1;
	x=d+10;
	h=8-x/60;
	m=0-x%60;
	if(m<0)
	{
  		h=h-1;
  		m=60+m;  
	}
	printf("%02d:%02d",h,m);
	return 0;  
 } 
       ```