#include<bits/stdc++.h>
#include<string.h>
using namespace std;

int main(){
	int s,v,time;//路程、速度、路程需要时间
	int h=0,min=0;//最后应出发的时间
	
	cin>>s>>v;
	if(s%v!=0)time=s/v+1;
	else time=s/v;
	
	time+=10;
	
	if(time>=60){
		h=time/60;
		min=time%60;
	}else min=time;
	
	if(h>=7){
		h=24+7-h;
		min=60-min;
	}else{
		h=7-h;
		min=60-min;
	}
    
	if(min>=60){
		min-=60;
		h++;
	}
	 
	printf("%02d:%02d",h,min);
	
	return 0;
}