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

int main()
{
	int s,v,h,m,sum;
	scanf("%d%d",&s,&v);
	if(s%v==0){
		sum=s/v+10;
	}
	else sum=s/v+11;
	h=sum/60;
	m=sum%60;
	if (60-m<10&&m!=0){
		printf("0%d:0%d",7-h,60-m);
	}
	else if(m!=0){
		printf("0%d:%d",7-h,60-m);
	}
	else{
		printf("0%d:00",8-h);
	}
}