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