#include <iostream>
using namespace std;
int main(){
	double s,v;
	cin>>s>>v;
	int t;
	int HH,MM;
	if(s/v!=(int)(s/v)*v) t=s/v+11;
	else t=s/v+10;
	int h1=t/60;
	int m1=t%60;
	if(h1>8) HH=8+24-h1-1;
	else HH=8-h1-1;
	MM=60-m1;
	if(HH<8&&MM>=10) cout<<"0"<<HH<<":"<<MM<<endl;
	else if(HH<8&&MM<10) cout<<"0"<<HH<<":"<<"0"<<MM<<endl;
	else if(HH>=8&&MM<10) cout<<HH<<":"<<"0"<<MM<<endl;
	else cout<<HH<<":"<<MM<<endl;
}