#include<bits/stdc++.h>
using namespace std;
struct jjy_time{
	int hour;
	int minute;
};
jjy_time jjy_t[2];
int main(){
	long s,v;
	cin>>s>>v;
	long t=s/v;
	t+=11;
    jjy_t[0].hour=8;
    jjy_t[0].minute=0;
    jjy_t[0].minute-=t;
    
	for(int i=0;i<=24;i++){
	if(jjy_t[0].minute>=60){
		jjy_t[0].hour+=1;
		jjy_t[0].minute-=60;
	}
		if(jjy_t[0].minute<0){
		jjy_t[0].hour-=1;
		jjy_t[0].minute+=60;
	}}
	if(jjy_t[0].hour<0){
		jjy_t[0].hour+=24;
	}
	
	if(jjy_t[0].hour<10){
		cout<<"0"<<jjy_t[0].hour;
	}else{
		cout<<jjy_t[0].hour;
	}		
	cout<<":";	
	if(jjy_t[0].minute<10){
				cout<<"0"<<jjy_t[0].minute;
	}else{
		cout<<jjy_t[0].minute;
	}	
	return 0;
}