#include<iostream>
#include<cmath>
#include<iomanip>
using namespace std;
int main (){
	int er,s,v,t,sum,sum1;
	cin>>s>>v;
	if(s%v==0) t=s/v+10;
	else t=s/v+11;
	sum=480-t;
	sum1=32*60-t;
	if(t<=480){
if(sum%60>=10)这里条件为2
cout<<"0"<<sum/60<<":"<<sum%60;
else cout<<"0"<<sum/60<<":"<<"0"<<sum%60;}
else {
	if(sum1/60>=10) {if(sum%60<=10)//这里条件为1
	cout<<sum1/60<<":"<<sum1%60;
	else cout<<sum1/60<<":"<<"0"<<sum1%60;}
	else {
	if(sum1%60<=10)
cout<<"0"<<sum1/60<<":"<<sum1%60;
else cout<<"0"<<sum1/60<<":"<<"0"<<sum1%60;}
}
return 0;
}