#include<iostream>
using namespace std;
int main(){
    int s,v;
    scanf("%d%d",&s,&v);
    int minutes=ceil(1.0*s/v)+10;
    int hh=7
    while(minutes>=60){
        hh=hh-1;
        if(hh<0){
            hh+24;
        }
        minutes=minutes-60;
    }
    printf("%02d:%02d\n",hh,60-minutes);
    return 0;
}