#include<bits/stdc++.h>
using namespace std;
int main()
{
	ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
	int T,t,h,m;
	float s,v;
	cin>>s>>v;
	t=ceil(s/v)+10;//向上取整 
  T=8*60-t;
	h=T/60;
	m=T%60;
	cout<<'0'<<h<<':'<<m;
	return 0;
}