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

int main()
{
    double s, v, t;
    int min, hour = 8;
    cin >> s >> v;
    t = ceil(s / v);
    min = t + 10;
    if(min / 60 > 0)
    {
        min %= 60;
        min = 60 - min;
        if(min / 60 > 8)
            hour = 24 - (min / 60 - 8);
        hour -= min / 60;
        hour -= 1;
    }
    else
    {
        min = 60 - min;
        hour -= 1;
    }
    if(hour < 10)
       cout << 0 << hour << ":";
    else
       cout << hour << ":"; 
    if(min < 10)
       cout << 0 << min << endl;
    else
       cout << min << endl;
    return 0;
}