#include<cstdio>
#include<cmath>
using namespace std;
int qread(){
	int num=0,f=1;char ch=getchar();
	while(ch>'9'||ch<'0'){if(ch=='-'){f=-1;}ch=getchar();}
	while(ch>='0'&&ch<='9'){num=(num<<3)+(num<<1)+ch-'0';ch=getchar();}
	return f*num;
} 

int Dayh=7,Daym=50;

int v,s;

int hours,minutes;

int main(){
	s=qread(),v=qread();
	minutes=ceil((double)s/(double)v);
	hours+=minutes/60;minutes%=60;
	
	if(minutes>50)	hours++,minutes-=50;	
	
	if(hours>Dayh)	Dayh+=24;
	
	printf("%02d:%02d",Dayh-hours,Daym-minutes);
	return 0;
}