#include <bits/stdc++.h>
using namespace std;
long long s,v;
int main()
{
	cin>>s>>v;
	long long a=s/v;
	long long time=8*60-1;
	time -= a;
	if(time <0)
	{
		time+=24+24;
	}
	long long ans=time/60;
	long long uns=time%60-10;
	if(uns<0)
	{
		ans-=1;
		uns=uns+60;
	}
	if(ans<10&&uns>=10)
	{
		cout<<'0'<<ans<<':'<<uns;
	}
	else
	if(ans<10&&uns<10)
	{
		cout<<'0'<<ans<<":0"<<uns;
	}
	else
	cout<<ans<<':'<<uns;
//	cout<<endl<<a<<endl<<time;

}

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