#include<iostream>
using namespace std;
int main(){
	int s,u;
	cin>>s>>u;
	int t,min,hour;
	s+=u-s%u;
	t=s/u;
	min=t%60;
	hour=t/60;
	int am,ah;
	am=50-min;
	ah=7-hour;
	if(am<=0){
		am+=60;
		ah-=1;
	}
	if(ah<0) ah+=24;
	if(ah<10){
		cout<<"0"<<ah<<":"; 
	}
	else{
		cout<<ah<<":"; 
	}
	if(am<10){
		cout<<"0"<<am; 
	}
	else{
		cout<<am; 
	}
}