#include <iostream>
#include <cstdio>
#include <cmath>
using namespace std;

int main()
{
    int s, v, t;
    cin >> s >> v;
    t = ceil(s / v) + 1;
    t += 10;
    int h = 7, m, a;
	m = 60 - t;
    if(60 - m < 0)
    {
    	a = abs(60 - m) / 60;
    	h -= a;
    }
    cout << h << ":" << m << endl;
    return 0;
}