#include<bits/stdc++.h>
using namespace std;
int main(){
    int s,v;
    scanf("%d%d",&s,&v);
    int minute;
    if(s/v!=0){
        minute=s/v+11;
    }else{
        minute=s/v+10;
    }
    
    
    int go_time;
    if(minute<=8*60){
        go_time=8*60-minute;
    }else{
        go_time=8*60+24*60-minute;
    }
    int hour=go_time/60;
    int mi_t = go_time%60;
    printf("%02d:%02d",hour,mi_t);
    
    
    return 0;
}