#include<bits/stdc++.h> using namespace std; int main() { int s,v; scanf("%d %d",&s,&v);

int t1 = s/v;                      
double t2 = (double)s/v;
if(t2>t1)
{
	t1 ++;
}
int n = t1 + 10;

int a=8,b = 60;

if(n>60)
{
	a = a-1 - n / 60;
	b = b -(n-60*(n/60));
 } 
 else
 {
 	a = 8-1;
 	b = b - n;
 }
 
printf("%02d:%02d",a,b);
return 0;

**

#include<bits/stdc++.h>
using namespace std;
int main()
{
	int s,v; 
	scanf("%d %d",&s,&v);
	
	int t1 = s/v;                      
	double t2 = (double)s/v;
	if(t2>t1)
	{
		t1 ++;
	}
	int n = t1 + 10;
	
	int a=8,b = 60;
	
	if(n>60)
	{
		a = a-1 - n / 60;
		b = b -(n-60*(n/60));
	 } 
	 else
	 {
	 	a = 8-1;
	 	b = b - n;
	 }
	 
	printf("%02d:%02d",a,b);
	return 0;
}

#include<bits/stdc++.h>
using namespace std;
int main()
{
	int s,v; 
	scanf("%d %d",&s,&v);
	
	int t1 = s/v;                      
	double t2 = (double)s/v;
	if(t2>t1)
	{
		t1 ++;
	}
	int n = t1 + 10;
	
	int a=8,b = 60;
	
	if(n>60)
	{
		a = a-1 - n / 60;
		b = b -(n-60*(n/60));
	 } 
	 else
	 {
	 	a = 8-1;
	 	b = b - n;
	 }
	 
	printf("%02d:%02d",a,b);
	return 0;
}