#include<iostream>
using namespace std;
int main()
{
    int s, v;
    cin >> s >> v;
    int time = 8 * 60;
    if (s % v == 0)
        time = time - s / v - 10;
    else
        time = time - s / v - 10 - 1;
    int h = (time / 60 + 24) % 24;
    int m = (time % 60 + 60) % 60;
    printf("%02d:%02d", h, m);
}