#include <bits/stdc++.h>
using namespace std;
int main(){
	double s,v,a,b,c,a1,b1;
	cin>>s>>v;
	a=8;
	c=s/v+10;
	b1=c%60;
	if(s<v*8*60){
		a1=c/60+1;
		a=a-a1;
		b=60-b1-1;
		if(b<10){
			cout<<0<<a<<":"<<0<<b<<endl;
		}else{
			cout<<0<<a<<":"<<b<<endl;
		}
	}else if(s>v*8*60){
		b=60-b1-1;
		a=24-c/60-1+8;
		if(a<10){
			if(b<10){
				cout<<0<<a<<":"<<0<<b<<endl;
			}else{
				cout<<0<<a<<":"<<b<<endl;
			}
		}else{
		
			if(b<10){
				cout<<a<<":"<<0<<b<<endl;
			}else{
				cout<<a<<":"<<b<<endl;
			}
		} 
	}else{
		cout<<"00:00"<<endl;
	}
    return 0;
}