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

int main()
{
	int s,v,t,a,b;
    cin>>s>>v;
    if (s%v==0) t=s/v+10;
    else t=s/v+11;
    a=(480-t)/60;
    b=(480-t)%60;
    if (a<10&&b<10) cout<<0<<a<<":"<<0<<b;
    else if (a<10&&b>9) cout<<0<<a<<":"<<b;
    else if (a>9&&b<10) cout<<a<<":"<<0<<b;
    else cout<<a<<":"<<b;
	return 0; 
}