#include<iostream>
using namespace std;
int main()
{
    int HH,MM,s,v,h;
    int min;
    cin>>s>>v;
    if(s%v==0){
    min=s/v+10;}
    else{
    min=s/v+1+10;}
    if((min/60.0)>1&&min/60!=1){
	h=(min-(min%60))/60;
    min=min-60*h;}
    else{
        HH=7;
        MM=60-min;
        cout<<"0"<<HH<<":"<<MM<<endl;
        return 0;}
        if(7-h<=0){
        h=7-h;
        h=24-(h+h*2);
        HH=h;
        MM=60-min;
        cout<<HH<<":"<<MM<<endl;}
        else{
            HH=7-h;
            MM=60-min;
            cout<<"0"<<HH<<":"<<MM<<endl;}
    return 0;    
}