#include<bits/stdc++.h>
using namespace std;
int n,m,a,b;
int c = 7, d = 60;
int main()
{	
	scanf("%d %d",&n,&m);
	a = ceil(1.0 * n / m);
	a += 10;
	b = a / 60;
	a %= 60;
	if(b > c)
	{
	    c += 12;
	}
	if(b > c)
	{
	    c += 12;
	}
	c -= b;
	d -= a;
	c += d / 60;
	d = d % 60;
	printf("%02d:%02d",c,d); 
    return 0;
}