#include<bits/stdc++.h>
using namespace std;
int main() {
	int s, v,time,x;
	cin>>s>>v;
	time=ceil(1.0*s/v)+10;
	x=8*60-time;
	if(x<0){
		x=1440+(8*60-time) ;
		if(x/60<10){
			cout<<'0'<<x/60<<':'<<x%60;
		}
		else
		cout<<x/60<<':'<<x%60;
	}
	else
	cout<<'0'<<x/60<<':'<<x%60;
	return 0;
}