#include<bits/stdc++.h>
using namespace std;
int s,v,t,h,m;
int main()
{
	cin>>s>>v;
    t=ceil(s/v)+10;
    if(t>480){
        h=t/60;
        m=t%60;
    }
    cout<<h<<":"<<m;


	return 0;
}