#include <cstdio>
#include <cmath>
using namespace std;
int main() {
    double s, v, a;
    int h, m;
    scanf("%lf%lf", &s, &v);
    a = ceil(s / v) + 10;
    h = (a >= 60) ? 8 - ceil(a / 60) : 7;
    m = (a >= 60) ? 60 - int(a) % 60 : 60 - int(a);
    printf("%02d:%02d\n", h, (m < 60) ? m : 0);

    return 0;
}