#include <bits/stdc++.h>
using namespace std;
int s,v,t;
int main(){
	cin>>s>>v;
	if(s%v==0){
		t=s/v+1+10;
	}else{
		t=ceil(s/v)+1+10;
	}
	if(t>60){
		int a,b;
		a=t%60;
		b=t/60;
		if(b<8){
			if(a<10&&b<10){
				cout<<"0"<<b<<":"<<"0"<<a<<endl;
			}else if(a>10&&b<10){
				cout<<"0"<<b<<":"<<a<<endl;
			}else if(a<10&&b>=10){
				cout<<b<<":0"<<a;
			}else{
				cout<<b<<":"<<a;
			}
		}else{
			b=24-b+8;
			if(a<10&&b<10){
				cout<<"0"<<b<<":"<<"0"<<a<<endl;
			}else if(a>10&&b<10){
				cout<<"0"<<b<<":"<<a<<endl;
			}else if(a<10&&b>=10){
				cout<<b<<":0"<<a;
			}else{
				cout<<b<<":"<<a;
			}
		}
	}else{
		if(t>50){
			cout<<"07:"<<"0"<<60-t<<endl;
		}else{
			cout<<"07:"<<60-t<<endl;
		}
	}
	return 0;
}