#include <iostream>
using namespace std;
int main(){
	long long s,v;
	cin>>s>>v;
	bool b=s%v;
	long long sum=10+s/v+b;
	int x=8,y=0;
	bool a=sum%60;
	cout <<"0";
	if(sum>=60){
		x-=sum/60+a;
	}else{
		x-=a;
	}
	if(x<0){
	    x+=24;
	}
	cout <<x;
	int a1=sum%60;
	cout <<":";
	if((60-a1)<10){
	    cout <<0;
	}
	cout <<60-a1;
	return 0;
}