#include<iostream>
#include<math.h>
using namespace std;
int main()
{
	float a,b;
	int c,h,m;
	cin>>a>>b;
	c=ceil(a/b);
	h=7-c/60;
	if (h==0) h=12;
	if (h<0) h=h+12;
	m=50-c%60;
	if (m<0)
	{
		m=m+60;	
	}
	if(h<10) cout<<"0"<<h;
	else cout<<h;
	cout<<":";
	if(m<10) cout<<"0"<<m;
	else cout<<m;
	return 0;	
}