#include<stdio.h>
int main()
{
    int s = 1; int v = 1;
    scanf_s("%d %d", &s, &v);
    int t0 = s / v;
    int t = t0 + 10;
    if (t <= 480) 
    {
        int hour = t / 60;
        int minute = t % 60;
        if (s % v == 0)
        {

            printf("0%d:%d", 7 - hour, 60 - minute);
        } else printf("0%d:%d", 7 - hour, 59 - minute);
    }
    else 
    {
        int t2 = t - 480;
        int hour2 =  t2/ 60;
        int minute2 = t2 % 60;
        if (hour2 > 22)
        {
            if (s % v == 0)
                printf("0%d:%d", 23 - hour2, 60 - minute2);
            else
            printf("0%d:%d", 23 - hour2, 59 - minute2);
        }
        else
        {
            if (s % v == 0)
            printf("%d:%d", 23 - hour2, 60 - minute2);
            else printf("%d:%d", 23 - hour2, 59 - minute2);
        }
    }
    return 0;
}