#include<bits/stdc++.h>
using namespace std;
int s,v;
int main()
{
    cin>>s>>v;
    int t=0;
    if(s%v==0){
    	t=s/v;
	}else{
		t=s/v+1;
	}
	t+=10;
    int h=t/60;
    int m=t%60;
    int h1=7;
    int m1=60-m;
    if(h<=7){
    	h1-=h;
	}else{
		h1=19-h;
	}
	cout<<h1<<":"<<m1;
    return 0;
}