#include<bits/stdc++.h>

using namespace std;

int s,v,m,h;

int main(){ 

	cin>> s >> v;
	if(s % v == 0){
		m = s / v + 10;
	}else{
		m = s / v + 11;
	}
	h = m / 60 + 1;
	m = m % 60;
	if(h >= 8){
		h = (h-8)%24;
		printf("%02d:%02d",h,60-m); 
		return 0;
	}
	printf("%02d:%02d",8-h,60-m); 
	return 0;
}