#include<iostream>
#include<cmath>
#include<cstdio>
using namespace std;
double a,b,t1,t2=10,t3,c=1440,d,e,h;
int f,g,i;
int main()
{
	cin>>a>>b;
	t1=a/b;
	t3=t1+t2;
	d=c-t3;
	e=d/60;
	f=trunc(e)-24;
	h=d-trunc(e)*60; 
	i=trunc(h);
	if (8+f>0)
	{
		g=8+f;
	}
	else
	{
		g=32+f;
	}
	if(g<10)
	{
	
		cout<<"0"<<g<<":"<<i;
	}
	else
	{
		cout<<g<<":"<<i;
	}
	return 0;
}