-----我是分割线-------

#include<iostream>
#include<cstdio>
#include<cmath>//07:50
using namespace std;
int main() {
    int s,v,t,t1;
    scanf("%d%d",&s,&v);
    if(s%v==0){
    	t=s/v;
    } else{
    	t=s/v+1;
    }
    t1=t/60;
    if(t1>7){
    	t1=24-t1+7;
    }else{
    	t1=7-t1;
    }
    t=t%60;
    if(t>50){
    	t1++;
    	t=abs(50-t);
    }else{
    	t=50-t;
    }
    
    printf("%02d:%02d",t1,t);
    
    return 0;
}