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