#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
int main(){
int s,v,n,x;
scanf("%d%d",&s,&v);
if((s/v)<470){
	n=7-((s/v+10)/60);
	x=59-(s/v+10)%60;
}
else{
	n=15+(s/v+10)/60;
	x=59-(s/v+10)%60;
}
printf("%02d:%02d",n,x);
	return 0;
} ```