#include <bits/stdc++.h>
using namespace std;

int main(){
	int s,v,w,t,h,m,ans;
	cin>>s>>v;
	w = s / v;
	if(s % v != 0) w += 1;
	t = w + 10;
	h = t / 60;
	m = t - h;
	if(h == 0) {
		h = 7;
		m = 60 - m;
	}
	else{
		h = 8 - h;
		m = 60 - s;
		if(m > 0){
			h--;
			m += 60;
		}
	}
	if(h - 10 < 0 && m - 10 >= 0){
		printf("0%d:%d",h,m);
	}
	else if(h - 10 >= 0 && m - 10 < 0){
		printf("%d:0%d",h,m);
	}
	else if(h - 10 < 0 && m - 10 < 0){
		printf("0%d:0%d",h,m);
	}
	else printf("%d:%d",h,m);
	return 0;
}