#include<bits/stdc++.h>
using namespace std;
int s,v;
int t;
int t1=7,t2=50;
int main()
{
	cin>>s>>v;
	if(s%v!=0)  t=s/v+1;
	else t=s/v;
	t2-=t;
	if(t2>=0)
	{
		if(t1>=10)cout<<t1<<':'<<t2;
		else cout<<"0"<<t1<<':'<<t2;
	}
	else
	{
		while(t2<0) 
		{
			t1--;
			t2+=60;
		}
		if(t1<=10) cout<<"0"<<t1<<':'<<t2;
		else cout<<t1<<':'<<t2;
	}
}